LaMotte POTASSIUM IN SOIL TTK User Manual

Pool Manager

Wa ter Quality Handbook

for aquatic specialists

PO Box 329, Chestertown, Maryland 21620

First printing December, 1989

1505 • 6/07

T able of Contents

Water Analysis ................................................5

Why? ............................................................

How?............................................................7

Water Sampling ..............................................9

Water Balance.................................................10

pH................................................................

Alkalinity ........................................................15

Calcium Hardness...........................................17

Temperature ...................................................19

Total Dissolved Solids (TDS) ...............................20

Water Sanitizers ..............................................21

Chlorine ........................................................

“Shocking” the Pool.........................................25

Cyanuric Acid.................................................

Bromine.........................................................28

Ozone...........................................................30

Alternative Systems..........................................32

Metal Systems.................................................32

Biguinide Systems ............................................32

Salt Chlorinators..............................................33

Hot Water/Spas...............................................33

Pool Problem Solver.........................................34

Algae (Nitrate and Phosphate) ...........................

Cloudy Water & Filtration ..................................36

Colored Water ................................................38

Stains ............................................................40

Scale.............................................................42

Eye & Skin Irritations.........................................44

Water Treatment Tables ....................................45

Lowering pH...................................................

Raising pH .....................................................47

Raising Chlorine..............................................47

Lowering Alkalinity ...........................................48

Raising Alkalinity..............................................50

Raising Hardness.............................................51

Raising Cyanuric Acid.......................................52

Water Analysis

Why?

The pool manager’s foremost responsibility is to maintain a safe recreational environment for the swimmer. To assure safety, the pool area must be evaluated regularly for possible sources of injury. To the inexperienced, a missing “No Diving” sign or an insufficient level of chlorine in the water may seem insignificant, but a properly trained pool manager recognizes that these are serious safety violations which require immediate attention.

Maintaining proper water quality is an extremely important part of an overall pool safety program. A water analysis serves three vital purposes: protecting the swimmer, protecting the pool, and protecting against wasteful chemical expenses. In addition. the pool manager balances the water so it is cosmetically clear and clean.

Protecting the swimmer

Every public pool is visited regularly by local health officials who conduct a water analysis while evaluating the overall safety of the pool area. The health official and the pool manager share the responsibility of protecting the swimmer. Cooperating with health officials to ensure that the swimming facility complies with state and local regulations is very important. The pool manager should have a copy of these regulations or codes and be familiar with them.

To prevent exposure to harmful bacteria, the most important water quality test is for adequate levels of sanitizer. Insufficient levels can cause swimmer irritations which may later lead to severe health problems. The most common sanitizers used in pool water are chlorine and bromine. These are used to prevent bacteria and algae within the pool and will be discussed later in detail in Chapter 3. The tests for pH

and alkalinity are also very important to the overall safe operation of the pool. Cloudy water, skin and eye irritation all result from improper pH and alkalinity levels in swimming pool water. The pH must also be properly maintained to maximize the sanitizing effectiveness of chlorine. The remaining tests which are performed on pool water are more important to the overall protection of the pool and its mechanical parts.

Protecting the pool

Maintaining a proper pH level is the first step toward protecting the pool. Corrosive conditions, which result from a low pH, can severely damage pool surfaces, plumbing, and cause bad staining problems.

Scale can result from a high pH and can clog waterlines, filters, and leave residues on pool surfaces and parts. By using daily water tests to make proper chemical adjustments, the pool and its parts are better protected, and should last much longer.

Protecting against chemical expense

The most common mistake made in treating pool and spa water is using improper amounts of chemicals. However, there are numerous occasions when chemicals are added in excess of the water’s actual need. This contributes to an imbalance in the pool chemistry, which can be harmful to both the swimmer and the pool, and as a result, more chemicals have to be added in order to bring the pool back into balance. In extreme cases swimmers may be restricted from using the pool.

Accurate water analyses should be used to determine which chemicals need to be added. Chemical treatment charts have been provided in the back of this handbook. While there is no substitute for formal instruction in operating a swimming pool, a retail pool professional should be consulted for advice on how to add chemicals.

How?

There are a variety of water test kits available to the pool manager. Each has its own unique set of directions which should be read very carefully. Though reagents may look similar from one kit to the next, the color standards in the color comparator or viewer can vary from one manufacturer to another. Therefore, it is important to realize that reagents or procedures are not interchangeable from test kit to test kit.

One of the most ignored, yet vital, directions in every test kit instruction is always to rinse and clean the test tubes and sampling equipment thoroughly. This should be done before and after each test. Unclean tubes can result in test container staining, and may inadvertently cause false readings if reagent or water remains in a container from a previous test.

When using a color comparator always read test results against a white background. If your comparator does not have a diffusion screen or a transparent white screen behind the color standards, it may be necessary to hold a piece of white plastic or paper behind the comparator when reading results. This procedure will neutralize background interferences which can significantly affect test results.

If you ever have trouble determining test results, take your kit, along with a water sample, to a local pool retailer or service professional for advice. Several “do’s” and “don’ts” are listed on the following page.

Do’s

1. Always hold reagent dropper bottles

vertically and squeeze gently to obtain a uniform drop size. Never hold dropper bottles on an angle.

2. Always fill test tubes so the bottom

of the water line is precisely on the indicated “fill-to” line.

3. Keep reagent bottles tightly sealed

and avoid excessive heat or freezing temperatures.

4. Keep DPD liquids away from heat.

Don’ts

1. Never leave the test kit where

children can find it or reach the components within the kit. Remember that safety is top priority.

2. Do not handle reagent tablets and avoid contact

with test reagents.

3. Do not store your test kit in direct sunlight or next

to water treatment chemicals. These may destroy instructions and slowly deteriorate components within the test kit.

Water Sampling

For best results the analyst should take samples from three to four areas around the pool each day. This can be especially beneficial in larger pools. Keep in mind that samples obtained on the surface should always be avoided since this may not be representative of the actual water chemistry. Several “do’s” and “don’ts” include:

Do’s

1. Rinse the sampling container several times with the

water to be tested.

2. Holding the sampling container sides, immerse to

elbow depth, approximately 15 inches or more below the surface, keeping the container six inches away from the side wall.

3. Always test the water sample promptly after

collecting it.

Don’ts

1. Never collect a sample

near a make-up water inlet, return area, or next to chemical feeders.

2. Nevertestawatersample

immediately following a shock treatment.

3. Never use a sampling container that is in any way

dirty or has a rusty lid—use plastic whenever possible. Glass should not be allowed in the pool area.

Water Balance

Corrosive

Balanced

Scale Forming

Water balance is defined as a condition where the water is neither corrosive nor scale forming. The factors in determining water balance include pH, total alkalinity, calcium hardness, temperature, and total dissolved solids (TDS).

Since water in motion tends to be corrosive, water balance is very important within the pool. To avoid corrosive conditions which can etch pool surfaces and mechanical parts, maintain all water quality factors within the proper range. Proper levels allow the water to become saturated, or non-corrosive, a key goal for prolonged trouble-free pool operation. When pool water becomes oversaturated with dissolved substances, especially calcium salts (primarily calcium carbonate), these substances fall out of solution and can make the water cloudy or deposit on pool surfaces. This is called scale and is a menace to pool surfaces and plumbing fixtures, clogging water lines and filters. As water balance is so important in maintaining the pool surfaces and parts, it constantly needs to be monitored with test equipment.

Pipe diagram

14 13 12

11 10

9 8 7 6 5 4 3 2

1 0

Basic

Neutral

Acidic

Bleach

Ocean Water

Pool Water

Orange Juice

Trichlor

(liquid Cl )

What is pH?

The term pH refers to the concentration of hydrogen ions in water. The pH test determines if a substance is acidic, neutral or basic. A substance with a pH of

7.0 is neutral, neither acidic nor basic. Those with a pH of less than

7.0 are acidic (orange juice has an acidic pH of

4.2). A pH above 7.0 is basic (ocean water is basic with a pH of about 8.0). The ideal pH for pool water is slightly basic, between pH 7.2 and 7.6. This range is most comfortable for the swimmer, protects the pool equipment, and allows sanitizers to work efficiently.

Why Do We Test pH?

The pH test is critical to protecting the pool. Though low or high pH levels can irritate swimmers’ eyes or skin, pH is normally considered the best indicator of overall “pool health.”

Controlling pH is critical for protecting the pool and its equipment from costly damages due to corrosive/acidic water or scale-forming/basic water.

For an indication of just how the pH affects the overall condition of the pool and its parts, other tests must be performed to obtain a clear answer. These tests are discussed later.

The pool water pH should be tested several times a day

LOW

If pH is too low (Acidic)

•

corrosion of pool equipment/staining swimming eye irritation etching plaster pool surfaces chlorine dissipates quickly

HIGH

If pH is too high (Basic)

•

scale accumulates on pool equipment cloudy, turbid water chlorine sanitizing power is weakened swimmer eye irritation

in a public pool with moderate-to-heavy swimmer usage. The pool’s pH level is constantly being changed by chlorine or other treatment chemical additions. Swimmer usage, additions of fresh make-up water, leaves, and debris can also alter the pH slightly.

The obvious reason to test pH is not only to identify a problem but to accurately decide how to remedy the problem. If a water test reveals a highly basic pH, such as

8.2, then the water supply needs to have an acidic substance added to bring the water back down to a pH of about 7.4. This need is called an “acid demand” and can be corrected by adding a liquid acid (muriatic acid) or a dry acid (sodium bisulfate).

If a water test shows an acidic pH level, such as 6.8, then a basic substance should be added to bring the water back up to a pH of about 7.6. This need is called a “base demand” and can be corrected by adding soda ash (sodium carbonate) to the water.

High pH Low pH

Acid Demand

Base Demand

See pages 44-45 for pH treatment charts.

How do we test pH?

pH is one of the most vital tests performed daily on pool water, anditisalsooneofthemost simple to perform. A single liquid or tablet indicator is used to provide a distinct pH color reaction which varies from yellow to deep red. This indicator (called Phenol Red) measures pH from 6.8 to 8.4. Most state public health codes require that pH color comparator be suitable for reading to 0.1 pH unit. Check local regulations to confirm that the on-site test equipment is in compliance.

Testing pH is simple: the test tube or sample cell is rinsed and filled to a specified line with sample water. Phenol red liquid or tablet is added to the sample as specified in the instruction. The sample is capped and mixed. The resulting colored solution is compared to color standards to determine the precise pH level.

Alternative methods of testing pH include two types of instrumentation. One is an electronic colorimeter which analyzes the color development with the phenol red pH test by passing a light beam through the sample. The amount of light that is absorbed by the reacted test sample determines the result, which is indicated by a meter display.

The pH meter relies upon a sensor called an electrode, which is immersed in a water sample. The electrode measures the electrical activity within the solution and displays the pH value. Though the pH electrode needs no phenol red reagent to provide a test result, it does need constant calibration with specific pH solutions (known as buffers) to assure accurate readings.

Paper test strips are gaining acceptance at public pools. Although they are utilized in smaller private pools and hot tubs, managers should check the local health regulations before using test papers as their only testing device.

Ideal Range for pH

7.2 - 7.6

Alkalinity

Ideal Alkalinity

Low Alkalinity

Allows to bouncepH

Allows proper pH control

High Alkalinity

Usually means high pH and is hard to adjust

pH reading

What is T otal Alkalinity?

Total alkalinity is a measure of the acid-neutralizing capacity of the water supply which enables it to resist abrupt changes in pH. Total alkalinity is commonly known as a pH stabilizer because, at proper levels, a consistent pH level can be maintained while treatment chemicals or fresh make-up water is added. Commercially available chlorine treatment compounds can range in pH from 3.0 to 13.0, and make-up water can range in pH from 5.0 to 8.0. Therefore maintaining total alkalinity at recommended ranges is extremely important.

Why do we test Alkalinity?

The purpose of testing alkalinity is to determine how susceptible the pool water is to rapid pH changes. A low level of total alkalinity allows the pH to fluctuate or “bounce” when materials are added, even in small amounts. A high level of total alkalinity can have the reverse effect, limiting the ability to change pH levels which may be too high. Total alkalinity is a measure of acid-neutralizing materials in the water, therefore it is

normal to see high alkalinity when the pH is also too high. A moderate or ideal alkalinity allows the pH to be maintained without requiring constant chemical adjustments. Alkalinity tests should be conducted once a week.

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