proper testing in salt water pools

Proper Testing Procedures Proper Testing Procedures in in

Salt Water PoolsSalt Water Pools(The Importance of Accurate Results)

Proper Testing Procedures Proper Testing Procedures in in

Salt Water PoolsSalt Water Pools(The Importance of Accurate Results)

By Ivars Jaunakais

Thursday September 26, 20131:00 PM -1:45 PM / 2 CE Credit Hours

• History and benefits of salt pools• The importance of balanced water• Different and proper water testing methods and techniques• What salt pool tests need to be done• How to easily verify that you, the test method, and reagent is

giving you correct answers

TOPICS

SALT POOL HISTORY

• Developed in Australia back in 1965• 80% of all Australian pools use salt• Introduced in USA in 1980• Popularity in USA finally caught on in

the last 10 years as technology improved

HISTORY

• In 2007 nearly 75% of American new pool installations were salt pools

• An increase of 15% from 2002• Currently over 1.6 million pools in the United

States use salt

BENEFITS

• Water is gentler on skin, eyes, nose and hair• Simple and convenient maintenance • Environmentally friendlier (less chemicals?)• Less expensive to operate in the long run• Less prone to algae problems

• Adequate generation of Chlorine by Salt System

• Regular testing of pool water• Weekly Cleaning and

Maintenance• Adequate circulation time• Quality filtration• Know what’s in the make-up

water to anticipate problems

MAINTAINING A SALT POOL

• Proper maintenance of salt pools begins with water testing

• Primarily for the safety of bathers• Avoids Liability issues • Accurate and routine testing results in less

problems• Testing is required to keep salt pools

balanced • Chlorine testing is required to know if Salt

System is adjusted properly

TESTING IS VITAL

• Weekly testing of pH and chlorine• Monthly testing during the season

for total alkalinity, calcium

hardness, metals, and cyanuric acid

• Monthly testing of salt levels need to match the proper level as specified by the chlorine generator manufacturer

TESTING IS VITAL

• Happy customers • Accurate test results

support correct maintenance, saving you and your customers money

• Increased business

SERVICE GOALS

• pH levels rise due to constant electrolysis (if problem continues consider Borate Buffer option)

• Requires more muriatic acid to keep pH OK• This lowers total alkalinity levels• Monitor Cyanuric Acid levels • Monitor Salt levels• Corrosion of metal parts• Higher electricity use

SALT POOL ISSUES

• Pool salt levels • Stabilizer levels• Control box settings• Pool circulation time

settings

COMMON ISSUES

• Poolside testing often performed in undesirable environmental conditions

• Temperature, humidity, sunlight, wind, and rain affect results

• Distractions including poolside activity and noise

POOLSIDE TESTING CHALLENGES

• Cost per test (varies $0.02 to $0.30 up to $10)• Time to run test (time = money)• Ease of use• Portability and stability of tests• Compliance testing requirements if testing

public or commercial pools and spas (meets State Health Department approval)

• Test gives good results with a test Standard

TESTING CONSIDERATIONS

• Be acceptable or compliant (i.e., Chlorine test uses DPD indicator)

• Use tests that don’t challenge your patience• Not be technically difficult• Use reagents and equipment that are safe,

reliable, and stable• Have good resolution (so precision is reliable)• Be accurate (answer is correct)

TESTING SHOULD…

• Colorimeters (Photometers) and reagents

• Titration or drop reagents

• Comparator test• Test Strips

COMMON TESTING TOOLS

Four colorimetric methods:1) Digital Photometer – uses different reagents

(liquid, powder, tablet, or reagent strip)

2) Colorimetric titration - counting drops and matching color using liquid and powder reagents

3) Comparator color test – uses liquid, powder, tablet, or reagent strip with a test tube or comparator color chart scale

4) Test strips - visual matching to a color chart scale

COLORIMETIC TESTS

• Uses colorimetric or precipitation chemistries and the color (or precipitate) is measured by a digital instrument that measures light transmission through sample

• Concentration is determined by the amount of light that is transmitted through the reacted pool water sample

• Chlorine has 0.01PPM resolution; 0.03 PPM accuracy• Hardness has 1PPM resolution; 10 to 20 PPM accuracy

TESTING TOOL #1Photometer and Reagent

(Most accurate method)

RESOLUTION EFFECTS ACCURACY!

Resolution 1 ppm Resolution 0.1 ppm

• Colorimetric chemistry that uses visual color change for testing concentration

• End point color change can be difficult to gage • Accurate counting of drops is required• Test is dependent on technique

(swirling is required )• Math required (drops are multiplied by

concentration factor) • Chlorine has 0.2 PPM (or 0.5PPM) resolution and

expect 0.6PPM (or 1.5PPM) accuracy• Hardness has 20PPM resolution; 60 PPM

accuracy

TESTING TOOL #2 Colorimetric (visual) titration

Commonly used FAS/DPD method

• Fast and inexpensive

• Minimum resolution & accuracy

• Liquid reagents have stability issues

• Requires good visual judgment

• Chlorine has 1PPM resolution and 3 PPM accuracy at lower levels

• pH has 0.3 resolution; 0.5 accuracy

TESTING TOOL #3 COLOR COMPARATOR

• Fast and inexpensive

• Suitable for screening

• Good shelf life

• pH resolution is 0.3 and accuracy is 0.5

• Chlorine resolution is 1 PPM or greater and accuracy is 3 PPM

• Available for most parameters

TESTING TOOL #4 Test strips

COLOR BLINDNESS

Over 32 million Americans (8% of men) are color blind

COLOR BLINDNESS

TESTING BEST PRACTICES

• Circulate pool water before collecting sample, or manually stir water in sample area

• Rinse sample cell/vial two or three times with pool water before sampling

• Sample water 18 inches below surface (most important for Chlorine, Bromine, and Cyanuric Acid testing)

TESTING Best Practices

• Do not collect water sample near return lines

• Note the temperature of water to be tested (Very cold or very hot water can effect test results)

• Read test instructions for procedure how to run test with very cold or very hot water


• Perform tests as soon as possible after collecting sample (immediate testing is required for accurate Free Chlorine results)

• If collecting samples for later testing, handle carefully to avoid contamination, fill bottle to capacity, & seal sample bottle tightly


• Pay careful attention to expiration dates on reagents and test strips

• Keep reagent containers tightly capped and store in a cool, dark place when posiible.

• Don't swap/mix the caps on reagent bottles to avoid chemical cross contamination


• Where required, measure volume of water sample to be tested (Measure the bottom of sample meniscus, not the top at fill mark)

• Don't interchange sample vials or cells

• Follow manufacturer’s test directions carefully


• Add liquid reagents carefully – make sure the correct number of drops are added to sample and drops are equal and full-sized

• Mix reagents with test samples thoroughly


Match visual test results under right conditions:

1.Proper lighting

2.Don’t wear sunglasses

3.Read colors against an appropriate background

4.Don’t match colors in bright sunlight


• Record results and maintain those records for each pool or spa

• Never dispose of tested samples/reagents in the pool

• Rinse sample test vials and cells immediately after testing


When using a photometer, verify your results using a Pool Water Standard to verify photometer, reagents, and operator

Pool Water Standards can also be used for verifying titration and comparator reagents


Average ACCURACY you can expect

IDEAL LEVELS for Salt Pools

CHEMICAL IDEAL LEVELS

Salt 2700 to 3400 ppm

Free Chlorine 1.0 to 3.0 ppm

Cyanuric Acid 60 to 80 ppm

Total Alkalinity 80 to 120 ppm

Calcium Hardness

200 to 400 ppm

Metals (Copper?)

0 ppm

Saturation Index

-0.2 to +0.2 (non-salt pools -0.05 to +0.05)

Nitrates at 0 PPM

BALANCED WATER

• Healthy Water = Balanced Water

• For balanced water 6 parameters to consider and they are used to calculate (Langelier) Saturation Index

1) pH

2) Total Alkalinity

3) Calcium Hardness4) Total Dissolved Solids (TDS)

5) Temperature

6) Cyanuric Acid (CY)

• Balanced Water is water that will neither scale nor corrode pool or spa surfaces and/or equipment

• Corrosion is the dissolving or wearing-away of pool wall, pipes or equipment (SI value below 0.2)

• Scale is the white deposit or precipitate that builds up on fixtures, surfaces, & equipment (SI value above 0.2)

• Balanced water is non-irritating to eyes & skin of bathers, & allows sanitizer to work effectively (SI is perfect when 0 but OK best between -0.2 to +0.2)

BALANCED WATER

BALANCED WATER

Amazon price - $13.89

• Protects bathers health – prevent transmission of infectious disease,

prevent skin irritation, respiratory problems, eye irritation; etc

• Protects Pool or Spa surfaces & Equipment from corrosion and/or

scale-formation, & discoloration

• Minimizes potential Health hazards from disinfection by-products

(combined chlorine is especially a problem for indoor pools/spas)

• Maintains compliance with Health Dept regulations

“Majority of pool problems are caused by poor water quality”

BALANCED WATER

• Chemicals found in make-up water, when treated by the municipal water treatment plant. Including disinfection by-products: lime, alkalis, phosphates and ammonia that forms monochloramines (combined chlorine compounds) in some chlorine treated systems

• Metals in make-up water is frequently found because pipes corrode as water flows through them

• Chemicals used to treat pool water - pH correction chemicals, sanitizers, oxidizers, stabilizer, chemicals for treating algae, mold, etc.

CHEMICAL SOURCES IN POOL WATER

• Bather sweat, urine, dirt, lotions, sunscreen,

cosmetics, soap residues, deodorant, hair spray, etc.

• Environmental items - debris, dirt, leaves ,

vegetation, etc., also contribute chemicals

• Disinfection by-products - trihalomethanes,

haloacetic acids, chlorate, nitrogen trichloride, etc.

• Rain water (can dilute your balanced water)

OTHER THINGS IN POOL WATER

COMMON PARAMETERS

CYANURIC ACID (CY)

• Used since 1956 in outdoor pools to protect chlorine from the Sun’s ultraviolet rays (Degradation)

• CY controls stability of the chlorine in the water but increases the amount of chlorine needed to maintain proper chlorine balance in pools

• CY buffers the pH against downward changes

• Contributes to the overall Alkalinity level

• Very important pool water parameter

CYANURIC ACID (CY) and 10x RULE

Effectiveness of chlorine protection to keep pool clean and algae free is influenced by the CY concentration RATIO to Free Chlorine concentration

• Ratio of 8 to10 times is suggested to be best for clean pools so for convenience I use 10 times (10X RULE)

• When the CY level is 40 PPM then keep Free Chlorine level at 4.0 PPM (10X RULE)

• So if your pool has 100 PPM CY then technically you should have 10 PPM Chlorine (10X RULE)

CYANURIC ACID (CY)

• CY forms weak reversible complex with Free Chlorine• CY does not affect Tests for Free Chlorine (FC)• CY/FC complex is affected by pH and concentration of

FC and CY• CY/FC Complex ties up as much as 95% of the Free

Chlorine. So if your pool water test reads 4.0 PPM FC then your complex free chlorine level is about 0.2 PPM

• As little as 0.01 to 0.05 PPM Free Chlorine is needed to keep pool clean according to CDC and World Health

CYANURIC ACID (CY)

• Effective concentration is 10 times the Free Chlorine concentration (10X RULE)

• Amount recommended to stabilize Free CL 10 ppm CY - 1.0 ppm Free CL 20 ppm CY - 2.0 ppm Free CL

30 ppm CY - 3.0 ppm Free CL 40 ppm CY - 4.0 ppm Free CL

50 ppm CY - 5.0 ppm Free CL

CYANURIC ACID (CY)

• If CY is NOT used in an outdoor pool anticipate 75% Free Chlorine degradation every 60 minutes on a sunny day

• Makes good economic sense to use CY for Free Chlorine protection – less chemicals = less money on Chlorine

• So with a Free Chlorine of 3.0 ppm in the pool then a good level of CY is 20 to 30 ppm

• NEW recommendations by CDC is to limit the CY level to a maximum of 60 PPM

• As CY increases, SI decreases so pool water becomes more corrosive

CY AND TA

• Cyanuric Acid (CY) effects Total Alkalinity (TA) in the pool• CY elevates TA and is influenced by the pH

Examples:

CY of 40PPM with 7.0 pH elevates TA by 8.8 ppm

CY of 40PPM with 8.0 pH elevates TA by 14.4ppm

• So If you keep CY levels at or below 40 ppm the TA effect averages about about 10 ppm and at this point you can ignore CY influence on TA.

• This is one more reason to keep CY below 40 PPM

CYANURIC ACID IN THE U.S.

One study 20 Years ago reported:• Average concentration – 76 ppm

• Maximum concentration – 406 ppm

• Another more recent study reported 25% (122 of 486) of private pools had more than 100 ppm

• CY is allowed for public pools in every State except New York

• CDC recommends CY levels below 60PPM because higher levels have potential PROBLEMS

My CYANURIC ACID (CY) guidelines

• The optimal level for cyanuric acid is 20 - 50 ppm• Levels above 50 ppm reduce chlorine effectiveness• Health Departments will close commercial pools above

100 ppm (Florida recommends 60 ppm) • When using CY maintain Free Chlorine using 10X

RULE • To reduce CY levels, partially drain pool and refill • Test and keep track of CY levels regularly if you use

Dichlor or Trichlor in your service

VARIATIONS IN CY LEVELS

CY levels at the bottom, mid- and surface-levels at the deep end of one Olympic-sized pool with poor water circulation were found to vary:

• Bottom – 100 ppm (12 feet)

• Mid-level – 50 ppm

• Pool surface – 20 ppm

• Photometric (1 ppm)

• Visual black dot comparator (over 20 ppm)

• Test Strip (over 50 ppm)

CYANURIC ACIDTEST METHODS (resolution)

• You need to use Photometric method to get accurate test results for Cyanuric Acid

• Very important when you want to keep CY between 20 - 50 ppm

CYANURIC ACIDTESTING IN THE FUTURE

TOTAL ALKALINITY (AL)

• AL is a measure of how much acid can be added to a liquid without causing a significant change in pH

• AL is the ability of water to resist a change in pH -“Buffering capacity”

• Water with AL of 80 to 120 PPM will resist wide & rapid fluctuations in pH (called pH bounce)

• AL is the bicarbonates, carbonates, & hydroxides in water

• Proper AL stabilizes pH


• If AL is low, pH will be affected by anything introduced into the

pool

• If AL is high, pH will be difficult to adjust (water will scale)

• Total Alkalinity is key to pH water balance

• Recommended that it should be adjusted FIRST, before pH

• Addition of acid or alkaline to adjust pool or spa Alkalinity will

change pH, and vice versa

Low Alkalinity (below 80PPM) can cause:• Wide and rapid pH fluctuations

• Corrosion of pool or spa and equipment

• Skin / Eye Irritation

• Cloudy water

• Adding acid like Muriatic Acid will lower pH & Alkalinity


• When you add supplemental Chlorine products anticipate their different pHs, and anticipate Alkalinity effect

• Ideal level is 80-100 ppm with CHLORINE sanitizers such as Sodium, Calcium, or Lithium Hypochlorite

• Ideal level is 100-120 ppm with CHLORINE sanitizers such as Dichlor, Trichlor, Bromine, or Chlorine Gas

• Maximum must be below 160 PPM NOTE: Parts per million (ppm) is equivalent to milligrams per liter (mg/L).


•Photometric (1 ppm)

•Titration (10 ppm)

•Test Strips (40 ppm)

TOTAL ALKAINITY TEST METHODS (resolution)

ORDER OF pH and AL ADJUSTMENTS

• pH is most important factor• Affects all other chemical / balance parameters• Determines acidity of water • Measured on a scale from 0-14 • pH 7 is neutral• Below 7 is acidic (e.g. lemon juice and coke)• Above 7 is basic or alkaline (e.g. baking soda

and concrete)

pH

• pH in the ideal range will be comfortable for human eye at 7.5

• Pool water pH is acceptable from 7.2 - 7.8

• Ideal pH range is 7.4 - 7.6

• pH levels should be tested DAILY!

• High pH reduces Chlorine’s effectiveness

pH

• pH meter (0.01 or 0.1)

•Photometric (0.1)

• pH comparator (0.2)

•Test Strips (0.2 or 0.3)

pH Testing Methods (resolution)

CALCIUM HARDNESS (CA)

• Defined as the amount of Calcium Salts in water (reported as Calcium Carbonate)

• Term Calcium Hardness used because hardness in tap water is due to Calcium

• Magnesium, barium & sulfate can contribute to Hardness

• Make-up water used to fill pool will vary in its calcium content depending on region of country / city or well water

• Ideal range is 200-400 PPM as CaCO3

• Maximum of 1000 PPM ?


• CA levels should be tested regularly

• Pool & spa water must have a certain amount of Calcium

• Calcium Hardness, when outside optimal range, can 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 water hardness allows corrosion or pitting of calcium rich surfaces such as concrete, plaster, & grout

•Photometric (1 PPM)

•Titration (20 PPM)

•Test Strips (over 50 PPM)

CALCIUM HARDNESSTEST METHODS (resolution)

TOTAL DISSOLVED SOLIDS(TDS)

• TDS is the total of all dissolved material in water

• TDS value is contributed and influenced by ions of

calcium, magnesium, sulfate, chloride, sodium,

potassium, phosphate, nitrate, all ions; Alkalinity;

Cyanuric Acid; and other chemicals present in water

• If it is dissolved in the water, it is part of TDS


High TDS levels ( over 1500 PPM) increase these undesirable events:

• Increases algae growth despite adequate sanitizer

• Corrosion despite water being otherwise balanced

• Cloudy water despite adequate filtration

• Eye and skin irritation

• Deposits on pool wall

• Salt pool TDS just add salt concentration: so 3500 PPM Sodium Chloride will add about 3500TDS

TOTAL DISSOLVED SOLIDSin Salt Pools

• TDS will increase in a salt pool over time

• Why? - chemicals are added, dirt and debris blow or wash

• water evaporation from pool

• If TDS exceeds 1500 ppm of initial level (like 5000PPM) monitor TDS, clarity, and SI

• TDS at even 8000 ppm can work but requires effort to keep track of SI

TESTING TDS

• TDS levels should be tested MONTHLY using 1. Digital Conductivity meter ($20 - $900)

(can do thousands of tests)

2. Test strips ($0.30 to $0.50 per test)

• Maximum TDS is 1500 ppm over start-up TDS• Some professionals find 5000 ppm TDS levels in pool water

acceptable

TEMPERATURE

• Temperature is a water balance factor but difficult to control

• Pool water is normally 78 - 82◦ F. • Spa water is normally 96 - 104◦ F• Test with digital or IR thermometer

• If pH goes up then Calcium Hardness and Alkalinity has to be kept at lower end (200 for CA & 80 for AL)

• Danger signs – pH above 7.8 and TA above 120

SI and RELATIONSHIP OF BALANCED WATER

SI (LSI)

SANITIZER AND DISINFECTANTS

• A disinfectant kills disease-causing organisms

• A sanitizer kills all microorganisms with impunity, (USEPA 99.9% effective) i.e. , chlorine

• Oxidation refers to the “chemical reaction” that organic contaminants or waste products undergo

• The pool environment is constantly exposed to new contaminants, two important considerations:

1. Sanitize water to kill microorganisms

2. Oxidize organic contaminants

CHLORINE

• Chlorine is the most popular worldwide sanitizer, disinfectant,

algae killer and oxidizer

• Chlorine is inexpensive, safe when used properly effective

• Chlorine doubles as a sanitizer and oxidizer in a pool or a spa

• Chlorine is most effective under certain conditions –

The pH is most important factor and must be in optimal range

for chlorine to be effective

CHLORINE

• Effective against a broad range of microorganisms • Over 79,000 tons are used in the United States and

Canada to treat water yearly• Monitoring chlorine concentrations is very important • Used in pools to protect bathers health, water clarity and

equipment• Inactivation of pathogens depends on contact time• In the United States, Health Departments require

all public pools to be routinely tested for chlorine

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

CHLORINE SOURCESS Salt Systems generate HOCl -------or NaOCl equivalent

ChemicalName

ChemicalFormula

Form % Chlorine

Chlorine Gas

Cl2 Gas 100%

CalciumHypochlorite

Ca(OCl)2 Solid 65-70%

SodiumHypochlorite

NaOCl Liquid ~12%

ABOUT CHLORINE SOURCES

Despite their chemical and physical differences, they form hypochlorous acid, or as more commonly known in the pool industry - Chlorine

This change occurs when added to water Hypochlorous acid (HOCl) is the effective

disinfecting agent

CHLORINE CHEMSTRY

• The sum of Hypochlorous acid (HOCI) and Hypochlorite ion (OCI ¯) is called free chlorine, and the chemical equation or relationship is:

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 causes

Hypochlorous acid to form Hypochlorite ion

HYPOCHLOROUS ACID REACTIONS

• Hypochlorite ion is less than one third as effective as 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

CHLORINE REACTION

• The SECOND REACTION is a series of chlorine reactions that occur with ammonia (NH3) and organic nitrogen compounds like proteins and amino acids in the pool to form chloramines

• Chloramines are less effective disinfectants

• Active chlorine can be transferred from inorganic chloramine to amine (organic) containing compounds

BREAKPOINT CHLORINATION

89

• 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” or “Super-Chlorination”

• Shock is required less frequently in Salt pools and depends on a variety of considerations

TOTAL CHLORINE

• Total chlorine is the sum of free chlorine and combined chlorine

• Free chlorine and total chlorine can be monitored by automated equipment and confirmed by poolside testing for swimmer protection

Total Chlorine = Free Chlorine + Combined Chlorine

• DPD methods have become preferred for chlorine measurement

• DPD methods determine concentration by measuring intensity of color formed when chlorine reacts with DPD

• DPD-FAS Titration method determines chlorine by measuring amount of FAS Titrant needed to bleach out DPD-chlorine color formed

• State health departments accept DPD tests because they are quick, enjoy wide acceptance & EPA approved

DPD CHLORINE TESTING

• DPD Photometric Digital Meter (0.01)

• DPD-FAS Titrimetric (0.2)

• DPD Colorimetric Comparator (1 or 2)

• TMB Test Strip (0.2 but only detects free chlorine)

EPA ACCEPTEDCHLORINE TEST METHODS(FREE AND TOTAL)

• Combined chlorine = TC - FC

• Free chlorine = 1.58 ppm (FC)

• Total chlorine = 1.89 ppm (TC)

• Combined chlorine = 1.89 – 1.58 = 0.31 ppm

Combined 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

TOTAL CHLORINE (TC) = FREE CHLORINE (FC) + COMBINED

CHLORINE

OTHER COMMON WATER QUALITY

PARAMETERS AND TREATMENT SOLUTIONS

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

• 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

PHOSPHATE

• Phosphorus is 0.12% of the earth’s crust

• Human bones and teeth contain 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 for algae growth

• Phosphate Testing is challenging below 0.2PPM (200ppb)

HOW PHOSPHATE GETS IN WATER

• Runoff from lawns • Rain water • Bathers

(sweat and urine)• Pool treatment chemicals• Leaves and debris

that is blown in

CONTROL ALGAE BY CONTROLLING PHOSPHATE

• Pool water will be regularly refreshed with City make-up water that may contain 1PPM phosphate

• Increase swimming pool chlorine level if phosphate is present.

• “Flock” the phosphate with a phosphate flock salt and vacuum.

• Rain water is usually OK

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 and 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

KEEP Salt POOLS PHOSPHATE FREE

• Test the water phosphate levels regularly• Avoid lawn/garden run-off from entering the pool• Remove leaves promptly • Keep phosphate below 120 ppb (0.12PPM)• Test the make-up water for phosphate (City water may

have as much as 1 PPM or 1000PPB phosphates)• Preferred photometric test uses molybdate reaction with

phosphate in mild acid solution to form molybdophosphoric acid or heteropoly blue complex

PHOSPHATE TESTING(resolution)

• Digital Photometric with reagent 0.01 PPM (or 10 PPB) resolution

• Test Strip with Comparator 0.1 PPM (or 100 PPB) resolution

• Ideally keep level below 0.1PPM or 100 PPB• If Chlorine is maintained above 4PPM and CY below

60PPM pool can tolerate 0.5PPM (500PPM) phosphate without algae problem.

SALT

• Salt in pool water also called salt chlorination

• Dissolved salt (1,800–6,000 ppm) is needed for the chlorination system

• The chlorinator uses electrolysis to break down the salt (NaCl +H2O = NaOH + HOCl).

• The resulting chemical reaction eventually produces Sodium HypoChlorite equivalent or NaOCl

• Saltwater pool utilizes a chlorine generator instead of direct addition of chlorine.

COMMERCIAL CHLORINE SALT GENERATOR

• Device that produces chlorine from a mixture of salt and water (brine) through electrolysis

• Chlorine used is produced through the electrolysis of brine

• Electrolysis uses two electrically-charged electrodes:

• Anode (positively-charged)

• 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.

SALT

• 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 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

• 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 (resolution)

• Photometric with SALT reagent (10 PPM)• TDS meters with Salt Algorithm (10 PPM) can be used but at

least once a year verify salt level with a second method (test strip or photometric)

• Salt Test Strips (500 PPM) and Salt Titrator Strips (100 PPM)• Most Salt System Manufacturers recommend accuracy of

500PPM for you testing

• Another word for cloudiness

• Caused by several factors:

1. Body-waste contamination

2. Non-organic suspended solids

3. Algae

4. Chemical imbalance (high alkalinity, high calcium)

• Turbidity is most commonly measured with a “turbidometric” meter – and is very accurate

• Can be tested with a photometer (less accurate)

TURBIDITY

Using STANDARDS to

Confirm Accuracy of your results

• Standards are used in an analytical chemistry laboratory to verify the accuracy of a test

• Standards are now available for pool service professionals

What is a “STANDARD?”

• To verify the working condition of your

instrument or test method

• To verify your results are accurate

• To ensure correct testing procedure is followed

• To verify reagents are good

Why use a “STANDARD?”

• Food, Medical, and Drinking Water

Agencies (Government regulators and

inspectors) require that your testing

equipment be confirmed by Standards

regularly.

• Liability is a big motivator

Why use a “STANDARD?”

• Ready Snap 1P requires no dilution: just twist open, fill test cell with sample, and run test

• Can be used with most instruments and test methods• Ampoule (10 ml of solution) contains Standard that is used

to verify your pool testing procedure and reagents• Ready Snap 1P are in plastic ampoules and are ideal for

pool service technicians

EXAMPLES OF STANDARDS

•Snap open a Ready Snap 1P Method Verification Standard by twisting the top 180°

Using READY SNAP with TITRATION STEP 1

• Squeeze plastic ampoule

to fill CELL to capacity

Using READY SNAP With TITRATION STEP 2

Add test tube sample to test bottle

Add colorimetric reagent (powder) to test bottle

Color will change from clear to red due to the presence of Calcium Hardness

Using READY SNAP With TITRATION STEPS 3 & 4

• Start titration: add drop by drop (count drops) Titration Reagent to test bottle and mix between each drop. Observe color

• Observe when color changes to PURPLE this indicates titration is near completion

Using READY SNAP With TITRATION STEPS 5 & 6

• BLUE color indicates end point (8 drops used)

• Multiple 8 X 20 equals 160PPM Total Hardness

• According to chart, this is borderline value

• Typical for titration accuracy

Using READY SNAP With TITRATION STEP 7

• Fill test vial with standard

• Dip test strip in standard sample for 5 seconds

Using STANDARDS in a STRIP SCANNER

• Wipe excess liquid with paper towel according to procedure

• Place strip into scanner channel

Using STANDARDS in a STRIP SCANNER

COMPARE RESULTS WITH CHART

• Turn on the Photometer and rinse out three times with clean water

• Break open a Ready Snap by twisting the top 180°

Using READY SNAP With a PHOTOMETER

STEP 1

• Squeeze plastic ampoule to fill photometer CELL to capacity (4mL)

• Discard this liquid sample followed with a quick shake of the meter to empty the CELL of the remaining water drops


STEP 2

• Select the MENU for the test method procedure you need verified (Calcium Hardness in this example) and run the test method

• Verify the displayed value result against the Solution Value chart (Next Slide)

Using READY SNAP With PHOTOMETER

STEP 3

Run the test method as you do normally using the correct procedure

Compare the displayed value against the assigned value chart provided below and on back


STEP 4

• If your value is within the acceptable range, you are operating the photometer correctly for this MENU test method

• If your value is borderline, review the manual and the proper procedure


STEP 5

READY SNAP Standard for TESTING:

• Pride in your work• Customers expect it• Health Departments require

it• Liability issues are bad for

business

STRIVE FOR BEST RESULTS

Questions? Ivars Jaunakais – Chief Analytical Chemist

[email protected] www.sensafe.com

DOWNLOAD THIS PRESENTATION: http://www.slideshare.net/sensafe

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/

proper testing in salt water pools

Education