understanding pool & spa water testing
DESCRIPTION
Test strips, Colorimeters, and test reagents are typically fast and easy to use for testing your pool water. You want them to produce results that are sensitive, accurate, and reliable. With accurate results you can simplify the maintenance of swimming pools and spas, which makes your customers happy. This leaves more time to sell your skills to new customers; and word will spread that you know how to keep a sparkling clean pool.TRANSCRIPT
UNDERSTANDING POOL & UNDERSTANDING POOL & SPA WATER TESTINGSPA WATER TESTING
By Ivars JaunakaisBy Ivars JaunakaisOrlando Pool and Spa Show • February, 2010Orlando Pool and Spa Show • February, 2010
R 021710
BEFORE WE BEGIN, I WOULD LIKE TO ASK…
Are you new in the pool service business? Have you done this for 5 years or less? Have you done this for over 5 years? Are you a pool builder?
TODAY’S TOPICS Recommended Florida health department
standards for pool and spa water quality Pool and spa water chemistry including
chemicals, their uses, and sanitizer / disinfecting systems
Water testing methods and testing techniques Pool water problems and treatment
A. DO YOU MAKE YOUR DECISIONS ABOUT POOL OR SPA MAINTENANCE THIS WAY?
I can make decisions based entirely on information gathered
I can make decisions based on information rather than a gut feeling
I don’t take people’s feeling too much into account when I need to make an important decision
B. DO YOU MAKE YOUR DECISIONS ABOUT POOL OR SPA MAINTENANCE THIS WAY?
I feel more comfortable if I consult an associate before a decision
I let my personal beliefs about pool maintenance impact my decisions
I am comfortable to make a decision if it “feels right” even if the decision isn’t supported by facts
TESTING IS IMPORTANT
Pools and Spas must be maintained in a conscientious way
Primarily for thesafety of bathers
Liability Good testing practices
reaps financial rewards
TESTING TOOLS
Test strips Colorimeters Test reagents
GOALS
Happy customers Produce accurate, and reliable results Accurate results supports the correct
maintenance saving time and money The time saved will allow you to develop new
customers
Over 12 million pools and 5 million spa in theUnited States all require maintenance
THE GOALis too maintain a pool or spa that …
is free from harmful microorganisms or pathogenic bacteria is free from algae is aesthetically pleasing (clean, clear, and inviting) does not irritate the eyes, respiratory system, or skin of
bathers is not stained or suffering from discolored water contains water that does not corrode contains water that does not deposit or leave residue does not have debris, scum, or foam floating on the
surface has no offensive odor
3 THINGS TO MAINTAIN A HEALTHY POOL OR SPA
Circulation Filtration Routine
Cleaningand Maintenance
STATE OF FLORIDA64E-9.004 Operational Requirements
State Pool and Spa Regulation Formerly 10D-5.133 Law took effect May 27, 2004 Can be found online -
http://www.flrules.org/gateway/ruleno.asp?id=64E-9.004&Section=0
(1) Water Quality (a) Cross-connection prevention (b) Bacteriological quality (c) Clarity (0.5 or less NTU) (d) Chemical quality
Chemicals used in controlling the quality of the pool water shall be tested and approved using the National Sanitation Foundation (NSF) Standard 60, 1996a 1997, which is incorporated by reference in these rules and shall be compatible with other accepted chemicals used in pools.
STATE OF FLORIDA64E-9.004 Operational Requirements
The following parameters shall be adhered to for pool water treatment:
pH – 7.2 to 7.8.
STATE OF FLORIDA64E-9.004 Operational Requirements
The following parameters shall be adhered to for pool water disinfection treatment:
Free chlorine residual shall be 1 milligram per liter (mg/L) to 10 mg/L, inclusive, in conventional swimming pools and 2 mg/L to 10 mg/L, inclusive, in all other type pools such as spa-type pools and interactive water fountains mg/L free chlorine or 6 mg/L bromine.
STATE OF FLORIDA64E-9.004 Operational Requirements
UNIT OF MEASUREMENTS
Primary unit of measurement for concentration is mg/L or parts per million (PPM) as more commonly used
1 PPM would be 1 part of item measured per 1 million parts of pool water or just 0.0001 %
The following parameters shall be adhered to for pool water disinfection treatment:
Bromine residual shall be 1.5 mg/L to 10 mg/L, inclusive, in conventional swimming pools and 3 mg/L to 10 mg/L, inclusive, in all other type pools. Except that, the following maximum disinfectant levels shall apply to indoor conventional swimming pools: 5 mg/L free chlorine or 6 mg/L bromine.
STATE OF FLORIDA64E-9.004 Operational Requirements
When oxidation-reduction potential controllers are required
Water potential shall be kept between 700 and 850 millivolts.
Use of these units does not negate the manual daily testing requirement of subsection 64E-9.004(13), F.A.C.
STATE OF FLORIDA64E-9.004 Operational Requirements
CHLORINE VS ORP READING
Cyanuric acid
1. 100 mg/L maximum in pools
2. 40 mg/L in spa poolsNOTE: Expect this level to be lower in the future
STATE OF FLORIDA64E-9.004 Operational Requirements
Quaternary ammonium
5 mg/L maximum in pools or spas
STATE OF FLORIDA64E-9.004 Operational Requirements
Copper –
1 mg/L maximum in pools or spas
STATE OF FLORIDA64E-9.004 Operational Requirements
Silver –
0.1 mg/L maximum in pools or spas
STATE OF FLORIDA64E-9.004 Operational Requirements
The pool recirculation system must be operated
The pool water level must be maintained All equipment and appurtenances should
be in good repair
STATE OF FLORIDA64E-9.004 Operational Requirements
When use of a public swimming pool requires an admission or a membership fee, the most recent pool inspection report shall be posted in plain view of existing and potential members and patrons.
Sanitary facilities shall be maintained Footbaths are prohibited
STATE OF FLORIDA64E-9.004 Operational Requirements
Test kits are required to be on the premises of all pools to determine
free active chlorine & total chlorine using N,N-Diethyl-p-Phenylenediamine (DPD)
bromine levels
total alkalinity levels
calcium hardness levels
pH
STATE OF FLORIDA64E-9.004 Operational Requirements
The following test kits shall be provided if the corresponding chemicals are used:
1) Cyanuric acid
2) Sodium chloride
3) Quaternary ammonium
4) Copper
STATE OF FLORIDA64E-9.004 Operational Requirements
When silver is added as a supplemental disinfectant, a water analysis must be done every six months and be submitted to the department upon request.
STATE OF FLORIDA64E-9.004 Operational Requirements
A test kit may be used for multiple pools, provided the pools have common ownership and they are located on contiguous property.
The test kit shall be capable of measuring the level of disinfectant in the normal operating range.
STATE OF FLORIDA64E-9.004 Operational Requirements
The keeping of a daily record of information regarding pool operation, using the Monthly Swimming Pool Report – DH 921 3/98, obtained from the local county health department, shall be the responsibility of the pool owner or operator.
http://www.doh.state.fl.us/environment/water/swim/download.html
STATE OF FLORIDA64E-9.004 Operational Requirements
STATE OF FLORIDA
DEPARTMENT OF HEALTH MONTHLY SWIMMING POOL REPORT
STATE PERMIT # DATE NAME OF POOL ADDRESS Days of month
Chlorine residual
pH
Filter Gauge Reading
POOL VOLUME IN GALLONS ___________________
9 AM 1 PM 4 PM 9 AM 1 PM 4 PM Vacuum
in/Hg
Pressure: Influent
PSI
Pressure: Effluent
PSI
Flow GPM
Pool Vacuumed
No. Patrons
Remarks Enter items such as: Total alkalinity, hardness,
cyanuric acid, equipment breakdown, excessive pool water loss, filter backwash, water clarity
1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Customized report forms may be substituted provided they contain the appropriate information and are acceptable to the department.
Report shall reflect manually conducted pool water tests for pH and disinfectant levels at least once every 24 hours
Retained at the pool or submitted monthly as required by the local health department
STATE OF FLORIDA64E-9.004 Operational Requirements
If fecal accident occur, the pool operator or owner shall consider the Centers for Disease Control's (CDC) “Fecal accident response recommendations for pool staff” found on the internet web site:
http://www.cdc.gov/healthyswimming/
STATE OF FLORIDA64E-9.004 Operational Requirements
DISINFECTION OF POOLAFTER FECAL ACCIDENT
OTHER BODY FLUIDS Vomit
1. Noroviruses germ hazard
2. Respond to the vomit accident as you would respond to a formed fecal accident, using CDC's recommendations
Blood
1. Germs don’t spread in properly chlorinated pool
2. There is no public health reason to recommend closing the pool after a blood spill
State Health Department Enforces these rules because swimmers leave behind:
Up to 50 ml of urine per swimmer (mostly by children)
100 ml of sweat per swimmer each hour
Up to 100,000,000 bacteria per swimmer
Organics like sunscreen, deodorant, hair spray, etc
Greatest concern is a fecal or diarrhea accident (resulting in release of Ecoli, cryptosporidium)
NOTE: Although there is no such thing as urine-detecting dye, you can make signs that prey upon this misconception that a urine indicator exists
WATER BALANCE
Defined as water that will neither scale nor corrode pool or spa surfaces and / or equipment
Corrosion involves the dissolving or wearing-away of a material
Scale is a white deposit or precipitate that builds up on fixtures, surfaces, and equipment
Balanced water is non-irritating to the eyes and skin of bathers, and allows the sanitizer to work effectively.
WATER BALANCE5 FACTORS THAT AFFECT IT
1. pH (PH)
2. Total Alkalinity (AL)
3. Calcium Hardness (CA)
4. Total Dissolved Solids (TDS)
5. Temperature
pH, AL, or CA is high, the water will deposit scale
pH, AL, or CA is low, the water will corrode
WATER BALANCE - pH
pH is a very important factor Affects all other chemical / balance parameters Determines acidity of water and is measured on
a scale from 0-14 pH of 7 is neutral Below 7 is acidic (e.g. lemon juice) Above 7 is basic or alkaline (e.g. baking soda)
WATER BALANCE - pH
pH in the ideal range will be comfortable for the human eye at 7.5
Pool water is acceptable from 7.2-7.8 Ideal pH range is 7.4-7.6 Testing should be done DAILY! A high pH, reduces Chlorine’s effectiveness
pH VERSUS CHLORINE SPECIES
Percent HOCl and OCl- vs. pH
0
10
20
30
40
50
60
70
80
90
100
6.0 6.5 7.0 7.5 8.0 8.5
pH
Per
cen
t H
OC
l an
d O
Cl-
HOCl
OCl-
HOCl
Hypochlorous Acid
OCl-
Hypochlorite Ion
WATER BALANCE - pH
WATER BALANCE - pH What causes pH to go up
Adding Alkali like Soda Ash Alkali Sanitizers like Sodium
Hypochlorite
TESTING pH Colorimetric visual tests
1. liquid test (using Phenol Red)
2. tablet test
3. test strips
Colorimetric test meter with pH indicator reagent
pH meter with electrode probe
1. Must be calibrated properly
2. Probe end is made of glass
TOTAL ALKALINITY (AL) The ability of the water to resist a change in pH
“buffering capacity”
The sum of bicarbonates, carbonates, and hydroxide in the water
Water with an appropriate amount of AL will resist wide and rapid fluctuations in pH (called pH bounce)
Proper AL stabilizes pH
Bicarbonate buffers essentially neutralize acids and alkaline before they can affect the pH
TOTAL ALKALINITY (AL)
If AL is low, pH will be easily affected by anything introduced into the pool
If AL is high, pH will be difficult to adjust (water will scale)
Total Alkalinity is the key to water balance and it is recommended that it should be adjusted FIRST, before pH
Anytime you add acid or alkaline to adjust the pool or spa AL, you will also be changing the pH, and vice versa
TOTAL ALKALINITY (AL)
Test WEEKLY Total Alkalinity is measured as Parts Per Million
or PPM Sanitizer used influences Alkalinity Different sanitizers have different pHs The ideal level is 80-100 PPM with sanitizers like
Sodium, Calcium, or Lithium Hypochlorite The ideal level is 100-120 PPM with sanitizers
like Dichlor, Trichlor, Bromine, or Chlorine Gas
TOTAL ALKALINITY (AL)Low Alkalinity can cause
Wide and rapid pH fluctuations Corrosion of pool or spa and equipment
Skin / Eye Irritation
Low pH Adding acid like Muriatic Acid will lower TA
TESTING TOTAL ALKALINITY (AL)
Colorimetric visual tests
1. liquid test (titration)
2. tablet test
3. test strips Colorimetric test meter with AL reagent
ORDER OF pH & AL ADJUSTMENTS
CALCIUM HARDNESS (CA)
Defined as the amount of Calcium Salts in the water (as Calcium Carbonate)
Term Calcium Hardness used because hardness in tap water is due to Calcium
Magnesium, barium and sulfate also can contribute to the Hardness
The water used to fill the pool will vary in its calcium content depending on your region of the country and city or well water
Ideal range is 200-400 PPM
CALCIUM HARDNESS (CA)
Should be tested MONTHLY
Pool and spa water must have a certain amount of Calcium
Calcium Hardness, when outside the optimal range, can either allow corrosion to occur or cause scaling.
Make-up water with high calcium is “hard water”
Make-up water with low calcium is “soft water”.
Low hardness allows severe corrosion or pitting of calcium rich surfaces such as concrete, plaster, and grout.
TESTING CALCIUM HARDNESS (CA)
Colorimetric visual tests
1. liquid test (titration)
2. tablet test
3. test strips Colorimetric test meter with CA reagent
CALCIUM HARDNESS (CA)
TOTAL DISSOLVED SOLIDS(TDS)
Total Dissolved Solids or TDS is the total of all the dissolved material in the water.
TDS value is contributed and influenced by ions of Calcium, magnesium, sulfate, chloride, sodium, potassium, phosphate, nitrate, and all other ions; Alkalinity; Cyanuric Acid; and all Chemicals present in the water.
If it is dissolved in the water, it is part of TDS.
TOTAL DISSOLVED SOLIDS(TDS)
TDS levels need to be known because high levels increase undesirable events:
1. Algae growth despite adequate sanitizer
2. Corrosion despite the water being balanced
3. Cloudy water despite adequate filtration
4. Eye and skin irritation
5. Deposits on the pool wall
TOTAL DISSOLVED SOLIDS(TDS)
Over time, TDS will increase in a pool Factors that cause this include chemicals
that are added, debris and dirt that blow or wash in, and the steady contribution of evaporation
If TDS reaches 1500 PPM above the level it was when the water was fresh, it is time to drain and replace the water (a maximum of 3000 PPM)
TOTAL DISSOLVED SOLIDS(TDS)
TDS may double in a year Not all disinfectant systems contribute equally to
TDS The use of Ozone will decrease the amount of
chemicals that are added; and therefore slowing the rise of TDS
Another easy way to reduce TDS is to ask that people shower before they get into the pool or spa
TESTING TOTAL DISSOLVED SOLIDS
Should test MONTHLY Conductivity meter ($20 - $300)
(can do thousands of tests) Test strips ($0.30 to $0.50 per test) Maximum is 1500 PPM over start-up TDS
TEMPERATURE
Temperature is an important water balance factor but difficult to control
Pool water is usually held at between 78-82◦ F. Spa water is held much higher at from 96-104◦ F Thermometer used for testing Test Frequency: Usually continuous monitoring
LANGELIER SATURATION INDEX (SI)
Developed In 1936 by Wilfred F. Langelier 5 factors influence the precipitation of Calcium
Carbonate (the formation of scale). The five factors are pH, Temperature, Alkalinity, Calcium Hardness, and TDS.
AL and pH have significant influence on SI and are the 2 factors most often adjusted to change SI
LANGELIER SATURATION INDEX (SI)
CA should always be adjusted if low TDS has the least impact of the 5 factors CA and TDS can be lowered effectively by
partial draining of the pool or spa Temperature is a large determining factor and is
difficult to control, hold, and adjust CA, TDS, and Temperature are factors we
should monitor
LANGELIER SATURATION INDEX (SI)
Mr. Langelier assigned a value to each of these Mr. Langelier assigned a value to each of these factors and developed an equation.factors and developed an equation.
SI = pH + TF (Temperature) + CF (Calcium Hardness) + AF (Total Alkalinity) – 12.1 (TDS)
LANGELIER SATURATION INDEX (SI)
SI = pH + TF (Temperature) + CF (Calcium Hardness) + AF (Total Alkalinity) – 12.1 (TDS)
When result is 0, the water is said to be chemically balanced (ideal goal)
Negative values will have corrosive tendencies
Positive values will have scale tendencies
The acceptable range for the SI is -0.5 to +0.5 (Within this range, the water in a pool or spa is satisfactorily balanced)
LANGELIER SATURATION INDEX (SI)
To calculate SI: First, test and record the 5 parameters Next, using Table 1, convert your test results for
Temperature, Calcium Hardness, and Alkalinity into the equation plug-in factors TF, CA, and AF
TDS does not have a chart. Instead use 12.1 if TDS is from 0-1000 PPM12.2 if from 1000-2000 PPM12.3 if TDS is above 2000 PPM
pH is used without alteration
LANGELIER SATURATION INDEX (SI) TABLE
Temperature °F = TF
Calcium Hardness = CF
Total Alkalinity = AF
32° = 0 5 = 0.3 5 = 0.7 37° = 0.1 25 = 1.0 25 = 1.4 46° = 0.2 50 = 1.3 50 = 1.7 53° = 0.3 75 = 1.5 75 = 1.9 60° = 0.4 100 = 1.6 100 = 2.0 66° = 0.5 150 = 1.8 150 = 2.2 76° = 0.6 200 = 1.9 200 = 2.3 84° = 0.7 300 = 2.1 300 = 2.5 94° = 0.8 400 = 2.2 400 = 2.6 105° = 0.9 800 = 2.5 800 = 2.9 128° = 1.0 1000 = 2.6 1000 = 3.0
LANGELIER SATURATION INDEX (SI) EXAMPLE
pH= 7.8 Temperature= 84° Calcium Hardness= 300 PPM Total Alkalinity= 200 PPM TDS: 1800 PPM
SI = pH + TF + CA + AF – 12.1 (TDS) 7.8 + 0.7 + 2.1 + 2.3 – 12.2 = +0.7 (Scaling)
LANGELIER SATURATION INDEX (SI)
To correct the water balance, we adjusted the Total Alkalinity to 100 PPM and the pH naturally lowered to 7.6
No change to Calcium Hardness level of 300 PPM is made (The Calcium Hardness cannot be lowered except by draining and refilling with water lower in Calcium Hardness)
Resulting SI will now calculate to be +0.2 or balanced!
LANGELIER SATURATION INDEX (SI) EXAMPLE
pH= 7.6 Temperature= 84° Calcium Hardness= 300 PPM Total Alkalinity= 100 PPM TDS: 1800 PPM
SI = pH + TF + CA + AF – 12.1 (TDS)
7.6 + 0.7 + 2.1 + 2.0 – 12.2 = +0.2 (OK)
SANITIZER AND DISINFECTANTS The pool environment is exposed to constantly introduced
things
Two important things must be done:
1. Sanitize the water to kill microorganisms
2. Oxidize organic contaminants
A disinfectant is an agent that kills disease-causing organisms
A sanitizer is an agent that kills all microorganisms with impunity
Oxidation refers to the “burning up” of organic contaminants or waste products
CHLORINE
The most popular sanitizer, disinfectant, algae killer, and oxidizer in the world is still chlorine
Inexpensive, safe (when used properly), and effective. In a pool or a spa, chlorine pulls double-duty as a
sanitizer, and as an oxidizer Chlorine is most effective under certain conditions. The
single most important factor is pH. The pH must be in the optimal range in order for chlorine to be effective
CHLORINE
Effective against a broad range of microorganisms Chlorine first used in 1908 for public healthMore than 79,000 tons of chlorine are used per year in
the United States and Canada to treat water Monitoring chlorine is very important Used in pools to protect people, water clarity and
equipmentSeveral pathogens can be transmitted in waterInactivation of pathogens depends on contact timePublic health requires pool water testing for
Hypochlorous acid or free chlorine residual concentration
7878
GERM INACTIVATION TIME IN 1 PPM CHLORINATED WATER
GERM INACTIVATION TIME
E. Coli O157:H7Bacterium
Less than 1 minute
Hepatitis AVirus
About 16 minutes
GiardiaParasite
About 45 minutes
CryptosporidiumParasite
About 15300 minutes(10.6 days)
pH 7.5, 77 °F
BACTERIA REGROWTH
RISKOF
ILLNESS
RISK OF ILLNESS
8282
SOURCES OF CHLORINE
ChemicalName
ChemicalFormula
Form % Chlorine
Chlorine Gas
Cl2 Gas 100%
CalciumHypochlorite
Ca(OCl)2 Solid 65-70%
SodiumHypochlorite
NaOCl Liquid ~12%
TYPICAL DEGRADATION RATE OF SODIUM HYPOCHLORITE
8484
ABOUT THE SOURCES OF CHLORINE
Despite their chemical and physical differences they all form hypochlorous acid
This change occurs when water is added Hypochlorous acid (HOCl) is the actual
disinfecting agent
8585
CHLORINE CHEMSTRY
The sum of Hypochlorous acid (HOCI) and Hypochlorite ion (OCI ¯) is called free chlorine, and the chemical equation or relationship is:
8686
HYPOCHLOROUS ACID REACTIONS Two chemical reactions impact the performance
of Hypochlorous acid as a disinfectant: First reaction involves a hydroxide ion (OH¯) OH¯ is available in aqueous solution especially
when pH level is above 7 which causesHypochlorous acid to form Hypochlorite ion
Hypochlorite ion is less than one third as effective a disinfectant as Hypochlorous acid
The next slide shows the relationship between pH versus chlorine species (Hypochlorous acid and Hypochlorite ion)
pH VERSUS CHLORINE SPECIES
Percent HOCl and OCl- vs. pH
0
10
20
30
40
50
60
70
80
90
100
6.0 6.5 7.0 7.5 8.0 8.5
pH
Per
cen
t H
OC
l an
d O
Cl-
HOCl
OCl-
HOCl
Hypochlorous Acid
OCl-
Hypochlorite Ion
8888
CHLORINE REACTION
Second chlorine reaction is with ammonia (NH3) and organic nitrogen compounds such as proteins and amino acids in the pool
A series of reactions occur that form chloramines
Chloramines are less effective as a disinfectant Active chlorine can be transferred from inorganic
chloramine to amine (organic) containing compounds
8989
COMBINED CHLORINE EQUATIONS
The sum of the chloramine species is called combined chlorine, and chemically created in the pool as follows:
9090
BREAKPOINT CHLORINATION
The process which eliminates both the combined chlorine and the ammonia problem responsible for creating the chloramine is called Breakpoint Chlorination In the pool industry its called “Shock” also called “Super-Chlorination”Shock is required daily, weekly or monthly and depends on a variety of considerations
EUROPEAN DIN REGULATION The German DIN regulation requires pools be
drained:
1. Once a month or
2. ¼ every week or
3. 1/30 every day Fresh water is added routinely which removes
chloramines (organic & ammonia) and other contaminates
Universal use of ozone and / or UV for pools and free chlorine levels are maintained at 0.4 to 0.6 ppm
9292
TOTAL CHLORINE
Total chlorine is the sum of free chlorine and combined chlorine Free chlorine and total chlorine are monitored by automated equipment and confirmed by poolside testing for swimmer protection
Total Chlorine = Free Chlorine + Combined Chlorine
9393
TO ACHIEVE GOODTEST RESULTS
Test is acceptable or compliant (uses DPD) Test is appropriate for the staff technical ability Test is robust, reagents and equipment are
reliable & stable Test is not affected by interferences Test is accurate when staff performs the test
correctly
9494
US EPA ACCEPTED TEST METHODS(ACCEPTED BY FLORIDA HEALTH DEPARTMENT)
DPD-FAS Titrimetric Method
DPD Colorimetric Meter Method
DPD Colorimetric Visual Method
DPD NOMENCLATURE
DPD-1 + DPD-2 is for free chlorine(liquid systems only)
DPD-1 is for Free Chlorine(Powders, tablets, test strips)
DPD-3 is KI(Potassium Iodide reagent) and applies to all except powders
DPD-4 is sum of DPD-1+DPD-2+DPD-3 (Total Chlorine)
9696
DPD DELIVERY METHODS
DPD-1, DPD-2, DPD-3 liquid reagents DPD-1, DPD-3, DPD-4 tablets DPD-1, DPD-4 powder pillows DPD-1, DPD-3, DPD-4 reagent delivery test
strips (All meet 4500-CL G reportable method) DPD is used for colorimetric or the DPD-FAS
Titration methods to determine the chlorine concentration
9797
DPD CHLORINE TESTING
DPD methods have become preferred for chlorine measurement
The DPD methods determine concentration from the color formed when chlorine reacts with the DPD
DPD-FAS Titration method determines the chlorine by measuring the amount of FAS Titrant needed to bleach out the DPD-chlorine color formed
Most state health departments recommend or accept DPD tests because they are quick, enjoy wide acceptance and have US EPA approval
9898
TOTAL CHLORINE (TC) = FREE CHLORINE (FC) + COMBINED CHLORINE
Combined chlorine = TC - FC
Free chlorine = 1.58 ppm (FC)
Total chlorine = 1.89 ppm (TC)
Combined chlorine = 1.89 – 1.58 = 0.31 ppmCombined chlorine is above the recommend level of 0.20 ppm and suggests pool needs to be shocked: in this example ( 10 X 0.31 = 3.1 ) this pool can be shocked by increasing the pool chlorine level by 3.1 ppm
9999
Free Chlorine, reference method versus test method
y = 1.0268x + 0.0126
R2 = 0.9998
0.00
2.00
4.00
6.00
8.00
10.00
0.00 2.00 4.00 6.00 8.00 10.00
reference method (ppm)
tes
t m
eth
od
(p
pm
)
CHLORINE TESTING
• Test Frequency: Daily/ multiple times/day depending on bather load•Ideal is 2.0-4.0 ppm in a pool and 3.0-4.0 ppm in a spa•High Chlorine level can cause Eye / skin irritation •Low Chlorine level can cause Illness and Disease and Skin irritation from such as a bacterial rash
COLORIMETER + LIQUID DPD POOLSIDE TESTING PROCEDURE
1. Rinse out photocell 3 times with pool water
2. Fill to 10 ml line with pool water sample
3. Cap cell, wipe cell wall
4. Place cell in colorimeter and zero meter
5. remove cell and uncap
6. add five drops of buffer DPD-1 solution
7. add five drops of indicator DPD-2 solution
8. cap cell and mix for a few seconds
9. wipe cell wall
10. place in colorimeter and read chlorine result
COLORIMETER + DPD-1 POWDER PILLOW POOLSIDE TESTING PROCEDURE
1. Rinse out photocell 3 times with pool water sample
2. Fill to 10 ml line with pool water sample
3. Cap cell, wipe cell wall
4. Place cell in colorimeter and zero meter
5. remove cell and uncap
6. Tear open powder pillow and add DPD-1
7. Cap cell and mix for 20 seconds
8. Wipe cell wall
9. Place in colorimeter and read chlorine result
COLORIMETER + DPD-1 TABLET POOLSIDE TESTING PROCEDURE
1. Rinse out photocell 3 times with pool water sample
2. Fill cell to 10 ml line with pool water sample
3. Cap cell, wipe cell wall
4. Place cell in colorimeter and zero meter
5. Remove cell, uncap cell,
6. Pour out water except for a few drops
7. Add DPD-1 Tablet and crush with tablet crusher
8. Add pool water back to 10 ml line
9. Cap cell and mix for about 20 seconds
10. Wipe cell wall
11. Place in colorimeter and read chlorine result
COLORIMETER + DPD-1 TEST STRIP POOLSIDE TESTING PROCEDURE
1. Rinse out photocell 3 times with pool water
2. Fill meter cell to capacity with pool water
3. Turn meter on and Zero
4. Dip DPD-1 Test Strip into sample for 20 seconds with back and forth motion (Press “READ” button that begins countdown timer)
5. Read chlorine result
NOTE: This is a recent development in DPD testing
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
Step 1 and Step 2
Rinse out photocell 3 times with pool water
Fill meter cell to capacity with pool water
Step 3
Turn meter on and Zero
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
Step 4
Dip DPD-1 Test Strip into sample for 20 seconds with back and forth motion (Press “READ” button that begins countdown timer)
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
Step 5
Read chlorine result
Free Chlorine = 1.58 ppm
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
Step 6 Continue the test to determine the
Total Chlorine concentration: Press “READ” button and simultaneously dip eXact® Strip Micro DPD-3 into the water sample for 20 second count down.
(During the 20 seconds constantly move the strip back and forth, which releases the Potassium Iodide reagent from the strip and mixes the sample)
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
Step 7 At the end of the 20 seconds the meter will
display “1” at which time you remove and discard the strip and the meter automatically reads and displays the total chlorine concentration, and stores the result in memory.
Discard sample and rinse with water before storage. This DPD test method is compliant for health department and US EPA requirements.
Total Chlorine = 1.89 ppm
NEW DPD METHODOLGY FOR POOLSIDE COMPLIANCE TESTING
FAS DPD POOLSIDE TESTING PROCEDURE1. Rinse out cell 3 times with Pool water sample
2. Fill to 25 ml line with pool water sample
3. Add five drops of buffer DPD-1 solution
4. add five drops of indicator DPD-2 solution (or one scoop of DPD Powder)
5. Swirl to mix for a few seconds
6. Add one drop of FAS reagent, swirl to mix and observe color
7. Add next drop of FAS Reagent, swirl to mix and observe color (Repeated for a total of 14 drops)
8. When pink color disappears Multiple 0.2 by number of drops you have used to make color disappear This sample has (0.2 X 14 drops) 2.8 PPM Chlorine
NOTE: This procedure has a total of 20 steps for this water sample
SPA WATER CHEMISTRY
Spas differ from pools because: 1. They have a much smaller volume2. They run at a much higher temperature
Bather load (and sanitizer demand) is much heavier than in a pool Smaller volume means that organics accumulate much faster, and
the demand placed on the sanitizer is much higher Greater sanitizer levels must be maintained (3-5 ppm for Chlorine,
4-6 ppm for Bromine) and testing must be carried out much more frequently – usually every 2 hours during periods of heavy use
Treatment is more demanding, because adjustments must be made more frequently, and measurements must be more precise.
SPA WATER CHEMISTRY
Small volume and increased sanitizer demand means that in Chlorine spas, Chloramines accumulate much faster than in a pool
Spas must also be drained at regular intervals if water quality is to be maintained
High temperature (above 100 degrees F) rises chemical reactions occur more rapidly
Chlorine reactions occur more rapidly, causing more rapid depletion High temperatures are conducive to the growth of certain disease-
causing bacteria like pseudomonas aerginosa High temperature contributes greatly to evaporation, which
concentrates TDS (Total Dissolved Solids) in the water Maintaining a spa presents unique challenges
SPA WATER DRAINING
Draining helps prevent TDS and Chloramine accumulation
The Association of Pool & Spa Professionals recommends draining and refilling spas at intervals according to the following equation:
1/3 X Volume of Spa (gallons)_______________________
Bathers per day
=Number of days
between drainings
1/3 X 300030
= 33
BROMINE Bromine is a chemical relative of Chlorine Used more commonly in spas because it is more stable at
high temperatures When Bromine combines with ammonia it becomes
bromamine which is still an effective sanitizer (does not irritate eyes and skin)
Bromine and bromamine are measured together as Total Bromine (Typically with DPD-1 Reagent)
More expensive than chlorine and can not be stabilized by cyanuric acid (rapidly dissipated by the sun)
Bromine comes most commonly in tablet form Bromine as a sanitation agent can not be switched over to
chlorine without completely draining and replacing the water
BROMINECHEMISTRY
Bromine's effectiveness dependent on the water's pH
Bromine breaks down in water forming Hypobromous
Acid (HOBr) and Hypobromite Ion (OBr -), the ratio of
the two being pH-dependent
At high pH, more of the OBr - is present
Recommended pH levels are the same for bromine
as for chlorine
HOBr is effective as an anti-algae agent
BROMINE
Test daily or multiple times depending on bather load
Typical recommended levels:2.0-4.0 ppm in a residential spa
4.0-6.0 ppm in a public spa Advantages:
Safe and easily handled Good sanitizer with no odor or irritation Bromine efficiency is less dependent on pH
Disadvantages More expensive than chlorine Acidic; destroys total alkalinity No stabilizer available (not recommended in Sun)
BIGUANIDES (PHMB)
Biguanides are unique for the pool marketThe term refers to a disinfectant polymer
polyhexamethyline biguanicide (PHMB)It is an effective sanitizer but not an oxidizerHydrogen peroxide must be applied as shock (monthly) Ammonium-based supplement is needed weekly PHMB concentrations need to be kept between 30 and
50 ppm and require a special test kitPHMB cannot be mixed with chlorine or any other
chemicals except those used as part of the package The result of doing so would be brown water and plaster stains
BIGUANIDE (PHMB) TESTING Test Frequency: Once per week or before swimming
Ideal levels: Concentration must be kept between 30 – 50 ppm Advantages:
Useful in case of chlorine allergies Less chemical smell Easy on eyes and skin Stable in sunlight Less frequent testing and treatment
Disadvantages Costlier than chlorine OR bromine May clog filters Not compatible with most pool maintenance chemicals Not approved for commercial pools
COMMERCIAL CHLORINE GENERATOR
Device that produces chlorine from a mixture of salt and water (brine) through electrolysis
Sometimes referred to as “salt generators” Chlorine used is produced through the electrolysis of brine Electrolysis uses two electrically-charged electrodes:
1. Anode (positively-charged)
2. Cathode (negatively-charged) Electrolyzing salt, the electrodes are contained in different
chambers because the result is chlorine gas and caustic soda, also known as lye, which should not be allowed to mix
The chambers are separated by a special membrane allowing sodium ions and electricity to pass through it, but not chloride ions or water.
COMMERCIAL CHLORINE GENERATOR
Generator converts:120 or 240 volts AC to 4 or 6 volts DC Residential pool unit requires about 20 amps Electric current passing through the membrane from positive to
negative splits the NaCl into chlorine gas and sodium Electric current carries sodium ions through the membrane to
the cathode chamber where it reacts with water to produce caustic soda and hydrogen gas
The hydrogen gas bubbles are vented off into the air The chlorine gas in the anode chamber passes through a tube
into the pool water By-product of this process is a small amount of hydrochloric
acid
COMMERCIAL CHLORINE GENERATOR
Anode chamber must periodically be refilled with water and salt The caustic soda can be re-used for adjusting the pool's pH
balance A typical chlorine generator designed for a 25,000 – 30,000 gallon
pool requires 45-50 pounds of salt, which must be replenished 2-4 times per year.
A similar unit can generate Bromine by using Sodium Bromide instead of Sodium Chloride as a generating source
Since chlorine and bromine generators produce water sanitizers continuously during operation, it is less necessary for chemicals to be added to the pool or spa water
Water must still be tested for sanitizer levels Equipment is expensive to buy and install. In addition to regular testing, chlorine or bromine generators
require salt level determination (Chloride or Bromide)
SALT TEST KITS
Colorimetric visual tests
1. liquid test (titration)
2. tablet test
3. test strips Colorimetric test meter with SALT reagent
(typical testing requires a dilution step)
OZONE GENERATION
Ozone is negatively-charged oxygen atoms Occurs naturally in the atmosphere, through the action of
lightning Non-toxic Useful water purifier, used for decades in municipal water
systems Reduces the amount of chemicals needed to combat algae and
bacteria Ozone has no effect on the pH balance, alkalinity or TDS of the
pool water, but it does NOT eliminate the use of chlorine Breaks down immediately on contact with water-borne
contaminants, but does not combat algae formation on pool and spa walls
OZONE GENERATION Can reduce the use of biocides and algaecides in a pool, it
is not a complete solution
Ozone generation involves the use of an ultraviolet (UV) or Corona Discharge (CD) unit which converts Oxygen (O2) to Ozone (O3)
Advantages:
Reduces the use of sanitizing chemicals
No effect on water balance
Disadvantages:
Ineffective against algae
High installation expense
IONIZATION OFCOPPER AND SILVER
Ionization is used for sanitation and has no effect on pH balance, alkalinity or TDS
Copper ions destroy algae; silver ions have a static effect on bacteria Ionizers use electricity to generate metal ions in the pool water Voltage generates positive ions Typical location of the electrodes is in an “ion chamber” located in
line between the pump and filter A control box varies the low-voltage DC charge (12-36 volts, .5-1
amp) to the electrodes that regulates the concentration of ions. One system may use only copper electrodes; another system may
use a copper and a silver electrode which produce both copper and silver ions
IONIZATION OFCOPPER AND SILVER
Excess copper ions in the water can cause staining
Copper level in the range of 0.15-0.2 ppm is recommended
The ion level is adjusted by changing the current flow across the electrodes, using a manual dial on the control unit
Ionization is not sufficient for complete sanitation of the pool water but can reduce the need of chemicals
Ionization manufacturers recommend weekly additions of an oxidizer (like potassium peroxymonosulfate) to remove organic contaminants and assist in combating algae
Advantages:
Can reduce use of sanitizing chemicals
No effect on water balance
Disadvantages
Copper ions cause staining
High installation cost
COPPERTESTING
Small concentrations of copper in the water can be beneficial as a biocide
Excess copper causes staining that can be very difficult to remove
Testing for the presence of copper can provide early warning of plumbing erosion or corrosion
If pool surfaces are being stained green or blue-green, or if bathers are complaining of green hair or blue fingernails, the water usually contains excess copper.
Copper concentrations can be tested with a visual colorimetric test, a liquid test, test strip, or colorimeter with Cu reagent
IRON
Iron in the pool water can be a source of black or red stains on pool surfaces
Above 0.1 ppm will cause the water to have a bad taste
Secondary drinking water regulation by the USEPA is set at 0.3 ppm (more of an esthetic than health issue)
WHAT IS IRON?
Iron is one of the most commonplace elements on Earth. Second most abundant metal (after aluminum) and fourth most abundant element.
Iron has the chemical symbol “Fe.” Because iron is very reactive, it does not exist
on its own. Iron is so common in the earth’s crust that at
least a trace is found in almost everything. Used in medicines.
IRON BECOMES AN ION
Fe Fe+2 (Ferrous) + 2 electrons
Fe Fe+3 (Ferric) + 3 electrons
Fe+2 + Cl2 FeCl2 (Ferrous Chloride)
2Fe+3 + Cl2 2Fe2Cl3 (Ferric Chloride)
4Fe+3 + 3O2 2Fe2O3 (Iron Oxide)
HOW IRON GETS IN THE WATER Make-up water drawn from a well If a metal component that contains iron begins to
rust it releases iron into the pool water
IRON REMOVAL
Chelating or Sequestering Agents work best
They prevent any iron coating on the pool walls
IRON TESTING
Colorimetric visual tests
1.liquid test
2.tablet test
3.test strips Colorimetric test meter with FE and Reducing
Reagents
HOW AN IRON TEST WORKS
Iron testing most frequently uses TPTZ powder pillows, test strips, or tablets containing in one unit, reducing agents, buffer and TPTZ indicator
Ferric iron + reducing agent = ferrous iron
TPTZ + ferrous iron = blue color
There is an inherent flaw in this test methodology. Turbidity issues (and most iron samples have turbidity) are addressed by adding an optional step, which is often ignored
This step, when ignored, can result in false low readings.
PHOSPHATE IS?
Phosphorus is about 0.12% in the earth’s crust
Human bones and teeth contain a large amount of calcium phosphate
Muscle, nerves and brains of animals, contain complex organic compounds of phosphorus, which are formed from vegetable matter
Red phosphorus is used for pyrotechnics and for the manufacture of safety matches and fertilizers
Phosphate is an essential nutrient and food for algae growth
PHOSPHATE BECOMES AN ION
P P+5 + 5 electrons 4P + 5O2 2P2O5
P2O5 + 3H2O 2H3PO4
(phosphoric acid) H3PO4 + H2O H3O+ + H2PO4
–
(dihydrogen phosphate) Ca(H2PO4)2 Calcium Dihydrogen Phosphate is
known as “Super Phosphate of Lime” and used as a fertilizer
HOW PHOSPHATE GETS IN WATER
Runoff from lawns Rain water Bathers (sweat and urine) Pool treatment chemicals Blown in leaves and
debris (soil and rock)
ANOTHER WAY TO CONTROL ALGAE GROWTH
In Florida, Catfish are used to eat the algae in abandoned pools
CONTROL ALGAE BY CONTROLLING PHOSPHATE
Pool water should be regularly refreshed with a fraction of new make-up water daily or weekly
Increase swimming pool chlorine level “Flock” the phosphate with a phosphate flock
salt and vacuum
SALTS THAT REMOVE PHOSPHATES
Iron salts (undesirable in pools)Used by municipal water and wastewater plants.Very effective in removing phosphate.
HPO4-2 + Fe+3 FePO4↓ + H+
Aluminum salts (inexpensive)Effective for levels above 1000 ppb.Does not remove phosphate below 100ppb.
HPO4-2 + Al+3 AlPO4↓ + H+
Lanthanum salts (expensive)Effective for maintaining low levels of phosphate.Easier to use and apply than Aluminum salts.Can drop phosphate levels below 100 ppb.
HPO4-2 + La+3 LaPO4↓ + H+
LATHANUM SALTS(chloride & sulfate)
Form a water insoluble Lanthanum Phosphate precipitate
Easily removed by the pool filter media In high concentrations, salts will not cause
cloudy water or staining of the pool
HOW TO KEEP POOLS PHOSPHATE FREE
Avoid lawn/garden run-off from entering the pool Remove leaves promptly Keep phosphate below 0.10 ppm (100 PPB) Test the make-up water for phosphate Test the pool water phosphate levels regularly Preferred colorimetric test uses molybdate
reaction with phosphate in mild acid solution to form molybdophosphoric acid (heteropoly blue complex)
PHOSPHATE TESTING
Colorimetric visual tests
1.tablet test
2.test strips Colorimetric test meter with PO4 reagent
TURBIDITY
Another word for cloudiness
Caused by several factors:
1. Body-waste contamination
2. Non-organic suspended solids
3. Algae
4. Chemical imbalance
Turbidity is most commonly measured with a “turbidometric” meter – and is very accurate
Can also be tested with a colorimeter (less accurate)
TEST METHODTurbidometric Tester
Measures the relative cloudiness, or turbidity of the water in NPT units
Turbidometric testing can be determined by a visual method but only at higher levels
Commonly measured with a Turbidometric meter which is measured by the light reflected from the undissolved materials in the water at a 90 degree angle
Colorimeter can also make this measurement as a transmission measurement but with less accuracy
BACTERIA
Bacteria are microorganisms that enter pool water through rain, blown-in contaminants, and the bodies of the bathers themselves. As previously discussed, the most important function of sanitizers is to combat these microorganisms.
Chlorine is introduced into a pool it breaks down into hypochlorous acid (HOCL) and hypochlorite ions (OCL-). Both of these kill bacteria by attacking the bacterial cell walls and oxidizing everything inside. Hypochlorous acid is able to oxidize most bacteria organisms in several seconds while hypochlorite ions can take over 30 minutes. Both can get the job done, but the time required.
Bacteria testing requires culturing the water.
18 MINUTE BACTERIA TEST
Commercial test methods include Immunological test that can confirm bacteria levels below 1000 colonies per ml run in 18 minutes
Reduces liability Gives confidence that pool is safe to reopen The Quick™ Bacteria Test is an antibody-based rapid
test kit for the presence of bacteria in swimming pools, spas and rivers, lakes or streams used for swimming. The Quick™ Bacteria Test detects E.Coli, species of Salmonella, Shigella, Enterobacter, Kliebsiella, and many other Coliform and non-Coliform bacteria.
COLORIMETIC TESTS
There are four basic colorimetic methods used in testing pool and spa water:
1. Colorimetric tests use a Colorimeter and reagent delivery device such as: liquid, powder, tablet, and test strip
2. Colorimetric visual using titration (counting drops)3. Colorimetric tests use a reagent delivery device
such as: liquid, powder, tablet, or test strip with a tube and a comparator color chart
4. Colorimetric visual test strips are used most commonly for testing these three parameters: Free Chlorine, pH, Alkalinity levels
LIMIT OF DETECTION (LOD) Applies more to instrument measurements Definition: MDL (minimum detection level) of
concentration that can be consistently detected For analytical tests LOD is typically calculated as
3 times the background noise
TEST METHOD #1Colorimeter and Reagent Most accurate DPD method
Colorimeters use colorimetric or precipitation chemistries and the color (or precipitate) is measured by an electronic instrument
No visual color matching They measure transmittance of light at a given
wavelength through the reacted water sample Most accurate of all tests
TEST METHOD #2 Colorimetric Visual using Titration
Commonly used DPD method Titrations use colorimetric chemistries
that require visual color change interpretation
Color change can be difficult to judge Accurate counting of drops is required Technique dependent (swirling) Math required
TEST METHOD #3 Colorimetric reagent with color chart comparator Inexpensive reagents
Gives only minimum resolution
Reagents may have stability issues
Requires good visual judgment
TEST METHOD #4 Colorimetric visual test strips with color chart Quick and easy Inexpensive Suitable for screening Good shelf life Does not use DPD
TEST METHODSAND EQUIPMENTConsiderations for Kit
Accuracy (0.03 to 3 or more) Resolution (0.01 to 0.8 or more) Selectivity (test reacts with the right ion) Dynamic Range
(6.0 to 9.0 for pH; 0.01 to 11.0 for Chlorine)
Limit of Detection (LOD)
TEST KITPERFORMANCE IN A LAB
Analysis will provide good results in a Laboratory setting
A lab is a controlled environment where Reagent stability is assured
Recalibration of test kit reagents or kit performance can be easily confirmed
TEST KITPERFORMANCE POOLSIDE (Challenges)
Test kits and instruments at poolside operate under harsh environmental conditions
Temperature, humidity, wind can have a great deal of affect on results and operator
Distractions like loud noise and high activity For some tests (especially Liquid reagents) stability is
affected by elevated Temperature and Sunlight Unfortunately precise results are a challenge at poolside
TEST METHODSAND EQUIPMENTConsiderations for Method
Price per test ($0.02 to $0.30 up to $10) Time to run test (30 seconds to 5 minutes) Easy to run test (Little or no operator
training required) Kit is portable and stabile Results are accepted by Health
Department
TESTING TECHNIQUES (best practices)
Let the circulation system run before taking your sample, or manually stir the water in the sample area
Rinse the sample vial two or three times with the pool water before taking your sample
Sample the water from 18 inches below the surface (especially important for the Free Chlorine measurement)
Do not take a water sample from near the return lines Make note (or at lease be aware approximately) of the temperature
of the water you are testing. Very cold or very hot water will affect colorimetric tests
Perform your tests as soon as possible after collecting the sample (immediate testing is required accurate for Free Chlorine results)
If collecting samples for later testing, handle carefully to avoid contamination and fill bottle to capacity and seal tightly
TESTING GUIDELINES (best practices)
Pay careful attention to expiration dates on reagents and test strips
Keep reagent containers tightly capped and in a cool, dark place
Don't swap/mix the caps on reagent bottles, or the chemicals may get cross contaminated
Where required carefully measure volume of the water sample to be tested (Measure the bottom of the sample meniscus, not the top at the fill mark)
Don't interchange sample vials or cells Follow the manufacturer’s test directions carefully
TESTING GUIDELINES (best practices)
Add reagents carefully – make sure the drops you add to the sample are equal and full-sized
Mix reagents with test samples thoroughly Match the visual test results under the right conditions:
1. Proper light
2. Do not wear sunglasses
3. Read the colors against an appropriate background
4. Do not match colors in bright sunlight
Record results and keep a log book at each pool or spa Never add reagents to the pool for flash testing (invalid) Never dispose used sample and reagent in the pool Rinse sample vials / cells well immediately after testing
HELPFUL RESOURCES
Book: Pool Chlorination Facts by Robert W. Lowry Book: Intermediate Training Manual Part 1-Chemicals by
Robert W. Lowry Book: The Ultimate Guide to Pool Maintenance by Terry
Tamminen Book: The Pool Maintenance Manual by Terry Tamminen
Internet: Florida Health Dept:
http://www.doh.state.fl.us/Environment/water/swim/index.html Internet: CDC http://www.cdc.gov/healthyswimming/
STRIVE FOR BEST RESULTS
Customer wants it State Health Department requires it. Liability for bad results
Any Questions? Ivars Jaunakais – Chief Analytical Chemist Ivars Jaunakais – Chief Analytical Chemist
[email protected] [email protected] www.sensafe.com
THANK YOU FOR YOUR ATTENTION!!