Superchlorination and Shock
Routine Chlorination
pH of Water
Total Alkalinity
Calcium Hardness
How To Test Pool Water
Water Clarity
How Chlorine Works
Water Troubleshooting Chart
DE Filter
Cartridge Filter
Sand Filter
Measure Pool Capacity in Gallons

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Super Chlorination and Shock Treatment


Recommended Dosage 5ppm

Pool Capacity in Gallons Shock How to Use
5,000 5 3/4 OZ. Follow label instructions for your type pool
10,000 11 1/2 OZ
20,000 23 OZ
35,000 40 1/2 OZ
50,000 57 1/2 OZ
Super-Chlorination is the addition of an extra dose of chlorine to bring the free available chlorine level to 5ppm. This will restore its ability to control algae and bacteria. Some algae spores can become immune to small regular doses. Super chlorination is recommended weekly when temperature is over 90o, your pool has high bather use, long periods of rain or high winds carrying debris and dirt.
Shock Treatment
is a larger dosage of chlorine sufficient to bring the free available chlorine level up to 10ppm. This is intended to control visible algae, burn out organic wastes and destroy excess "Chloramines". These chloramines can be responsible for strong chlorine odors and eye irritation. The use of SHOCK, periodically with your chlorination routine, will aid in prevention of undesirable side affects. DO NOT resume swimming until chlorine residual drops below 3.0 ppm.

Recommended Dosage 10ppm

Pool Capacity in Gallons Shock How to Use
5,000 12 OZ. Follow label instructions for your type pool
10,000 24 OZ
20,000 46 OZ
35,000 80 OZ
50,000 115 OZ

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Chlorine Treatment

When you add chlorine to your pool it will react chemically to destroy or alter such things as bacteria, perspiration, urine, algae and many forms of organic material. The term for the amount of chlorine required to kill and oxidize all contaminants is CHLORINE DEMAND. If you have a dirty pools with lots of contaminants your chlorine demand will be high, if you have a clean pool, the chlorine demand will be low. If sufficient chlorine was added to oxidize all pollutants, a demand would no longer exist.
To keep pool water effectively sanitized it is necessary to build up a residual of chlorine which is free and available to do its job of sanitizing. Thus, the term FREE AVAILABLE CHLORINE. an excess of free chlorine of 1.0-1.5 ppm will destroy any new contaminants entering the pool.
Once the chlorine reacts with pollutants, it forms what is known as CHLORAMINES (Combined Chlorine). While a simple test kit using OTO may indicate the presence of chlorine in the water, this is in a reality only COMBINED and FREE CHLORINE, referred to as TOTAL CHLORINE.

Free Chlorine+Combined Chlorine = Total Chlorine

TOTAL CHLORINE is not a true measurement of bacteria killing free chlorine and is not considered to be an adequate sanitizer. Only FREE CHLORINE is effective and it can only be measured with a FREE CHLORINE TEST KIT ( DPD or test strips)

5,000 1 1/4 OZ 1 TAB Use float feeder or automatic feeding device. Keep adjusted to provide 1.0 - 1.5 FREE AVAILABLE CHLORINE
7,500 1 3/4 OZ 1 TAB
10,000 2 1/4 OZ 1-2 TAB
12,500 3 OZ 2 TAB
17,500 4 OZ 2-3 TAB
20,000 4 1/2 OZ 2-3 TAB
25,000 5 1/2 OZ 3-4 TAB
35,000 8 OZ 4-5 TAB
50,000 12 OZ 6-7 TAB
-- Scatter over pool Place in Skimmer
NOTE: All dosages are approximate. Actual dosages will vary according to weather conditions, water temperature, number of swimmers and pH. Fast Tabs dosage based on 1 TAB per 7,500 gallons daily.

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pH is a measure of the alkalinity or acidity of pool water on a scale of 0 to 14. The pH level is by far the most important factor in water balance because it affects the ability of your chlorine to kill bacteria, and to control damage to pools and equipment.
A reading of 7.4 to 7.6 is ideal. 7.2 to 7.8 is acceptable. Below 7.0 is acidic, 7.0 is neutral and above 7.0 is alkaline.
Use a reliable test kit to check pH and use pH INCREASE or pH DECREASE to keep pH in balance. Never add more than 2 lbs. of chemical per 10,000 gallons in a single treatment. Run the filter and allow at least 4 hours before re-testing to determine if more is needed.


Pool Capacity


---- 6.8-7.2



5,000 1/4 lb 1/2 lb 3/4 lb
10,000 3/4 lb 1 lb 1 1/4 lb
20,000 1 1/2 lb 2 lb 2 1/2 lb
35,000 2 3/4 lb 3 1/2 lb 5 1/4 lb
50,000 3 3/4 lb 5 lb 6 1/4 lb
Pool Capacity pH TEST READING
--- 7.8-8.0 8.0-8.4 8.4-8.7 8.7-9.0
5,000 1/4 lb 1/2 lb 3/4 lb 1 lb
10,000 1/2 lb 1 lb 1 1/2 lb 2 lb
20,000 1 lb 2 lb 3 lb 4 lb
35,000 1 3/4 lb 3 1/2 lb 5 1/4 lb 7 lb
50,000 2 1/2 lb 5 lb 7 1/2 lb 10 lb

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Total Alkalinity is the total concentration of the alkaline chemicals in water. While not the same as pH, it does control pH to a large degree. The ideal TOTAL ALKALINITY range of 80-150 ppm makes pH control easier. Above 150 ppm, pH has a tendency to bounce back to its initial high level. When below 80 ppm pH tends to be very sensitive and difficult to control. Measurement can be obtained with a Deluxe Test Kit or 3 Way Test Strip.
If Alkalinity is too low, add ALKALINITY PLUS as per label or table below. If Total Alkalinity is too high, use MURIATIC ACID.

Pool Capacity To Raise 10 ppm To Raise 20 ppm To Raise 30 ppm
5,000 3/4 lb 1 1/2 lb 2 1/4 lb
10,000 1 1/2 lb 3 lb 4 1/2 lb
20,000 3 lb 6 lb 9 lb
35,000 5 1/4 lb 10 1/2 lb 15 3/4 lb
50,000 7 1/2 lb 15 lb 22 1/2 lb
NOTE:Do not add more than 1 pint of MURIATIC ACID or 1 lb of pH DECREASE per 10,000 gallons of pool water at any one time. With filter circulating, re-test after 4 hours to determine if additional application is needed.
The accepted level for TOTAL ALKALINITY of swimming pool water is from 80-120 ppm. Levels up to 150 ppm are acceptable in pools with vinyl liners.
Pool Capacity 150 ppm 200 ppm 240 ppm 280 ppm
5,000 4 pints 7 3/4 pints 5 1/2 pints 7 quarts
10,000 4 quarts 7 3/4 quarts 11 quarts 14 quarts
20,000 7 3/4 quarts 4 gallons 5 1/2 gallons 7 gallons
35,000 3 1/2 gallons 6 3/4 gallons 9 1/2 gallons 12 1/4 gallons
50,000 5 gallons 9 3/4 gallons 13 3/4 gallons 17 1/2 gallons
Pool Capacity 150 ppm 200 ppm 240 ppm 280 ppm
5,000 5 lb 9 1/2 lb 13 3/4 lb 17 1/2 lb
10,000 10 lb 19 1/2 lb 27 1/2 lb 35 lb
20,000 20 lb 40 lb 55 lb 70 lb
35,000 35 lb 67 1/2 lb 137 1/2 lb 175 lb

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to Raise Hardness
Pool Capacity 11 ppm 22 ppm
5,000 1/2 lb 1 lb
10,000 1 lb 2 lb
20,000 2 lb 4 lb
35,000 3 1/2 lb 7 lb
50,000 5 lb 10 lb
The measurement of soluble calcium salts will give you CALCIUM HARDNESS. In swimming pool water, calcium hardness will vary with the water source, previous chemicals used such as calcium hypochlorite and rate of evaporation of the water. High levels, above 300 ppm in conjunction with other factors, may cause cloudy water and scaling of pool surfaces.
Low levels, below 100 ppm, may lead to etching of plaster in concrete pools. CALCIUM HARDNESS CONTROL can be added to raise low calcium hardness.

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The chlorinating chemical you will be using in the pool as a disinfectant is a very active chemical. It is easily dissipated by the ultra-violet rays of the sun. To prolong useful life of free available chlorine, the addition of BOOSTER is recommended when filling the pool. It keeps the sunlight from burning up the chlorine. The ideal range is 30-50 ppm.
Pool Capacity Dosage
5,000 1 1/2 lb
10,000 3 lb
20,000 5 3/4 lb
35,000 10 lb
50,000 14 1/4 lb

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Testing WaterYour pool water can be affected by many factors. Testing is the only reliable way to monitor the proper chemical balance and is recommended on a daily basis.
LEISURE TIME POOLS has several different test kits which test for various water conditions. The "Test Strip" provides a simple, reliable test for Free Chlorine which is the most active in swimming pool water. Proper pH and Total Alkalinity insure swimmer comfort, longer equipment life and maximum chlorine effectiveness.
LEISURE TIME recommends that you bring a sample of water from your pool for analysis of factors which can not be tested within the home kit. We recommend two times a year, once in the spring and once in the fall before winterizing. Use at least a pint sized, clean container, rinsed in the pool water before collecting sample. DO NOT let the sample get hot from leaving in the car all day. For best results bring to store immediately after collecting.

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When the sunlight hits the surface of a perfectly clear pool, it is reflected from the ripples and creates a sparkle like diamonds. When the sunlight hits surface of a pool that has high levels of suspended particles, the light will be diffused and not reflect back giving a very dull appearance. Consequently, the water looks hazy and uninviting. But, most of all it will cause the chlorine to be used up prematurely. Suspended particles in water are the primary cause of turbid, dull, cloudy water. These particles are present for one or more of the following reasons:

1. Improper Filtration
  • Not running pump long enough.
  • Filter not working properly.
  • Type of Filter not compatible with pool and surrounding conditions.

2. Heavy Bather Load

  • More swimmers than system can handle.
  • Too many small children peeing in the water

3. Improper Water Balance

  • If the water is out of balance on the scaling side, calcium particles will go into suspension causing cloudy water.
4. Algae Formation
  • In its early stages, algae cause cloudiness in the water. This condition is usually accompanied by a slick slimy feel on various parts of the pool.

The secret of water clarification lies with the ability to control the amount of suspended solids regardless of the source. So when your water turns cloudy, it's extremely important to determine the reason and take action to remove it.


1 Feel walls and areas behind ladders. If a slime is present that indicates formation of algae Make sure pH is adjusted to 7.2-7.6. Superchlorinate immediately. Continue to filter until water clears, keeping chlorine levels at 1.5 ppm or above
If Step 1 finds no algae present proceed to next step.
2 Check pH, Total Alkalinity and Calcium Hardness. If any of these are high an "out of balance" condition is indicated. Take whatever action is necessary to get the water back in balance. Continue to filter until the water clears, keeping chlorine at above 1.5 ppm.
If step 2 shows the water to be in balance proceed to next step.
3 Most water clarity occurs because of inadequate filter care. Make sure you have a regular maintenance program. Here are some things to check:
Sand Filter
1. Is pressure coming up?
2. Has sand been changed?
3. Are you backwashing too often?
DE Filter
1. Is filter running at high pressure?
2. Are you cleaning filter properly?
3. Does your filter need an acid bath?
Cartridge Filter
1. Does cartridge need cleaning?
2. Does cartridge need acid bath?
If the steps above fail to solve your problem, you should consider the following:

USE OF CHEMICAL CLARIFIERS: Particles that cause cloudiness stay in suspension because each charge has an electrical charge that repel each other causing the particles to be to light to sink to the bottom. As a last resort this cloudiness can be removed by using a water clarifier. There are basically two types of clarifiers. One is a coagulant which is a chemical that when added to the water causes the small partic0les to stick together (floc) making larger chemicals which are filterable. Several "flocs" coming together (flocculating) will cause the heavier particle to settle to the bottom. DO NOT USE FLOCKING CHEMICALS WITH DE FILTERS.
Another type of clarifier is an ionized polymer. The polymer has a positive charge and is attracted to the negative charged dirt particles which become big enough to be filtered or settle to the bottom.

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How Chlorine Works

What do we want to accomplish by using a sanitizer. in our pool water?
  1. Kill bacteria and germs
  2. Reduce Organic matter
  3. Prevent algae growth
How do we accomplish this with a sanitize?
  1. Disinfection
  2. Oxidation
DISINFECTION- To kill bacteria and disease producing micro-organisms which might infect swimmers if not destroyed. These microscopic creatures are living organisms too small to be seen by the naked eye and are constantly being introduced into the pool by rain, wind and the swimmers.
OXIDATION- is to react with and destroy other contaminants which cause color, odor and cloudiness. Examples of these contaminants would be; suntan lotions, body oils, perspiration, dust and dirt.
What are we trying to kill and oxidize?
  1. Micro-organisms
  2. Organic matter
MICRO-ORGANISMS- Bacteria, algae, fungi and viruses are some of the living micro-organisms that get into the pool whether carried by the swimmer or the wind. Most of these organisms are harmless to the human body but some are...disease and infection...causing. If not killed, these germs multiply and are transmitted at public pools and water parks.
ORGANICS are introduced to the pool mostly by the swimmer, for example, a person can lose as much as two pints of perspiration an hour, the chemistry of perspiration is almost the same as that of urine. Add the other standard wastes found in a pool such as expectorate, nasal discharge, fecal matter and urine...then you begin to appreciate the job to be done by the chlorine sanitizer.
How does chlorine work?
To understand how chlorine works it will be necessary to go into more depth than normal in pool water chemistry.
Organic contaminants and micro-organisms consume chlorine. This consumption is called CHLORINE DEMAND and is the amount of chlorine required to react with and destroy contaminants before any chlorine is left un-reacted. In other words how much does it take to do the job.
When added to water all chlorine products produce hypochlorous acid (HOCL). If one understands the chemistry of hypochlorous acid, one will have a head start on control of chemical costs. Lets examine a couple of simple examples.
Calcium Hypochlorite + water = hypochlorous acid + Calcium ion
[Ca(OCL)2] + H2O = HOCL + Ca+2
Wasn't that easy? Lets try another one.
Chlorine Gas + water = hypochlorous acid + Muriatic Acid
Cl2 + H2O = HOCL + HCL
Hypochlorous acid will exist in the molecular state as HOCL the most active form, or the ionized form OCL- which has only about 1% of the killing power.
Does Chlorine react differently under different conditions?
Yes, lets examine four different reactions of HOCL:
Disassociation of HOCL - being an acid HOCL will disassociate (break up) into hydrogen ions H+ and the hypochlorite ion OCL-. What determines the amount of each is the pH of the water. As the pH of the water increases so does the non killing Hypochlorite ion OCL-. That's why pools with high pH have more trouble with algae and bacteria. Keep the pH at 7.2-7.4 for best ratio of HOCLvs.OCL-.
Reaction with Bacteria and Organics -when Hypochlorous acid (HOCL) kills bacteria or oxidizes organic material, it loses its properties and becomes a Cloride ion (Cl-). In other words after the chlorine does its job it reverts to chloride (salt)
Reaction with Ammonia(NH3) - ammonia is one of the by products of the human body, through perspiration and urine. It can also be found in the pool from fertilizers and cleaning products. The reaction of HOCL with ammonia produces a series of chlorine-like odorous, irritating compounds called chloramines or combined chlorines. These chloramines irritate the eyes and nose and are confused with pool chlorine. Combined chlorine has little or no killing power.
Reaction with Sunlight- when HOCL is exposed to the ultra violet rays of sunlight it will be reduced to chloride salts. On a bright sunny day 90% of the chlorine can be lost in two hours. That's why we recommend using stabilizer/conditioner which keeps the sunlight from burning up the chlorine.
How Does Chlorine Affect Algae Growth?
The best and cheapest algaecide (algae killer) is a properly maintained sanitizer level from 1-3 ppm chlorine. When the chlorine levels fall to unsafe levels, algae spores will start to grow. Within 12 hours a pool can turn completely green from algae bloom. Once this occurs it takes 30 ppm chlorine to kill algae.
This is all a little above my head can you help?
Sure what you need to accomplish is,
  1. Kill bacteria and germs to keep the water healthy.
  2. Burn out all that other nasty stuff that gets in the water

If you do those things you will also help prevent the growth of algae.

All this is accomplished by:
  • using a good grade of chlorine.
  • keeping the pH adjusted.
  • proper filtering.
  • keep the free chlorine at 1.0-3.0 ppm
  • keep the pH at 7.2-7.6

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ALGAE Green or mustard-brown algae. Green water, slippery surfaces, cloudy water Insufficient free chlorine Adjust pH, Shock and add algaecide
BLACK ALGAE Black Algae spots Insufficient Free Chlorine Adjust pH, scrub spots
Insufficient free chlorine of chloramines Adjust pH, shock with SCORCH PLUS
CHLORINE ODOR Strong odor burning eyes Early Algae Growth Shock with SHOCK
CLOUDY WATER Hazy, cloudy water, no sparkle Low Total Alkalinity Add ALKALINITY PLUS
Calcium Suspension Use HYDROFLOC
Poor Filtration Check Filter, run it longer
Low Calcium Hardness Add Calcium Hardness
EYE, SKIN IRRITATION Red eyes itching skin Improper pH Adjust pH
SCALE FORMATION Scale deposits on walls, pipes, filter, heater High pH Add pH DECREASE
High Hardness Lower Alkalinity, Dilute pool water. use METAL MAGIC
COLORED WATER Brown Iron Adjust pH, Shock w Shock Add Metal Magic
Black Manganese
Blue Green Copper
CORROSION of METALS Metal Corrosion, rust stains, copper stains, colored water Low pH Add pH INCREASE Add METAL MAGIC
HIGH CHLORINE USE Excessive use of chlorine Heavy swimmer load, dirt, high temperatures Super Chlorinate w/SHOCK
Low Stabilizer level Add BOOSTER

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Many pool professionals consider DE filtration to be the best, because it is capable of filtering out smaller particles than either cartridge or sand.
How clean must swimming pool water be? Any of the other types of filters can produce clear water, but for those that want the purest and most sparkling, the choice is DE. DE is short for diatomaceous earth a porous powder made from the skeletons of billions of microscopic animals that died and were buried in deposits millions of years ago. Magnified many times, they resemble small sponges or pieces of wood that have been eaten by termites or carpenter ants. Clear water can pass through the microscopic openings, but particles larger than one to three microns will be trapped.
Unlike sand and cartridge filters--which may vary in outward appearance but are identical in operation --DE filters differ in methods of operation. The type with which this writer is familiar, the HAYWARD PERFLEX FILTER, uses vertical, flexible, porous Flex Tubes as the internal elements. This will be the type referred to in discussing operations, but all types of DE filters have internal elements that are coated in some manner with DE.

When water containing DE passes through each of these elements, a thin, even coating of DE forms on the outside of the elements through which water circulates. The term for this is "pre-coating". It is this "filter cake" that strains the dirt, dust, algae and some forms of bacteria from the water. Just one pass through the "cake" clarifies the water to sparkling cleanliness. DE filters, no matter which type used, will clean water down to one to three microns. It is important to remember this, because all DE filters sometimes are faulted for short cycling, or clogging up too quickly. When this happens, it is because the filter is doing its job -- trapping pool contaminants one to three microns or larger.

INITIAL STARTUP Close the filter drain or plug if the filter has one. open the suction and return valves if they exist. Close any vent valve on the filter tank. Prime and start the pump, following the manufacturer's instruction. Air trapped in the system will be vented into the pool, so there is no need to open any manual air vents. When there is a steady flow of water returning to the pool, the filter is ready for precoating. Do not run the filter for more than one minute without the precoat charge.
PRECOATING - Scoop the proper amount of DE filter powder into the system through the skimmer, as fast as the plumbing will take it. Note and remember the pressure reading after the DE has been added. This is the "precoat pressure"
FILTRATION -Filtration starts as soon as the filter has been precoated. As the filter removes dirt from pool water, the accumulated dirt causes a resistance to flow. As the dirty water from the pool filters through the DE cake, dirt collects on its outside surface. After several days, or when the pressure rises 7 to 10 lbs. above the precoat pressure, the accumulated dirt begins to block the DE, diminishing the filters outflow.
BUMPING - Filtration is restored to near original flow by a process called regeneration (Bumping), in which the clogged cake is removed from the elements, mixed thoroughly internally, and then reapplied to the elements. To "Bump" the filter, turn the pump off, open the vent valve, move the handle down slowly then up briskly. Repeat 3 times. Close the vent valve on the tank, restart the pump and filtration will resume at near the original flow and pressure. This distributes the dirt within the DE and provides a fresh outer filtering surface. The filter can be regenerated whenever you need maximum filter flow, such as when vacuuming or during and after heavy pool usage.

CLEANING - Eventually, usually after three to ten weeks of operation the filter will need cleaning and a fresh supply of DE. When the pressure rises more than 10 psi in less than a 24 hour period (If the pool is not extremely dirty), simply switch off the pump, " bump off" the filter cake, open the drain valve and allow the dirt and old DE to drain out. No disassembly is required, and the complete operation takes about five minutes (Follow instructions in the owner's manual).
Here are some "Don'ts" to remember when operating DE filters:

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Cartridge Filters


Cartridge filtration has been around for a long time, but it only recently has begun to enjoy rapid growth and acceptance. This is due partly to the better quality built into today's elements. Some earlier cartridge filters (and a few today) had inferior quality elements, which are the heart of the design.
Cartridge filter shapes do not vary much. The single cylinder, with an easy opening top for access and cartridge removal, is the most popular and convenient design. Several manufactures utilize a cluster or grouping go two, four six or eight smaller diameter tubes using smaller elements. Another design has a tank that clamps to a base. Access to the elements in this filter requires that the clamp be loosened to allow the entire filter body to be lifted off to expose the internal parts for cleaning or servicing.
Whatever the shape, all cartridge filters are identical in how they clean water. They are simple devices that trap dirt, lint, dust and pool debris as the water passes through the pleats, flowing from the outside of the elements to a collector standpipe, or core, and back to the pool return lines.

INITIAL STARTUP-- be sure the filter drain plug or cap is closed. Open the manual air vent valve a few turns, and open the suction and return valves in your plumbing system, if used. Be sure locking knobs or caps are secure...hand tight is sufficient. Prime and start the pump, following the manufacturer's instructions. Air trapped in the system will vent automatically to the pool and out the vent valve. Close vent valve as soon as air is vented.
Filtration starts as soon as flow is steady through the filter. As the filter cartridge removes dirt from the pool water, the accumulated dirt causes a resistance to flow. As a result the gauge will rise and the return flow will decrease. When the pressure rises 7 to 10 pounds above the starting pressure, or when the flow decreases below desired rate, clean or replace the filter cartridge or cartridges.

Remove the cartridge element(s) in the following manner.

  1. Shut off the pump.
  2. If the filter is located below water level close valves or block off suction and discharge lines to prevent backflow of water from the pool.
  3. Unscrew and remove drain plug from filter tank and allow to drain from filter. Close drain.
  4. Unscrew and remove locking knob (to lid).
  5. Carefully lift off top cover to gain access to filter cartridge.
  6. Lift out cartridge and clean, replace with clean spare cartridge.

The cartridge filter element can be pressure washed inside and out with a garden hose. Algae, suntan oil and body oils can form a coating on the cartridge pleats that may not removed thoroughly by hosing. To remove such materials, soak the cartridge in a solution of filter element cleaner. Tri-sodium-phosphate (TSP) also is widely used with great success. Follow the manufacturer's directions for use.
Hose the cartridge thoroughly before reinstalling in the filter. Remember the chemical or cleaner you use will only loosen, or to a degree, dissolve the grime, calcium, etc., on the cartridge. The jet action from a strong garden hose must be used to clean thoroughly down into the bottom or deepest parts of the pleats or folds.
If calcium or mineral deposits are excessive, the cartridge may be restored to "like new" condition by soaking in muriatic acid. Use commercially available 20o Baume muriatic acid added to water in a one to one ratio.Use a plastic container, and take extreme care when handling cleaning agents, because they can be harmful to eyes, skin, and clothing. After cleaning flush with water.
A spare cartridge element is an excellent investment. It provides convenience and assures that your filter will always be ready to operate at peak efficiency.

Reinstalling Cartridge

  1. Clean any dirt or debris from the bottom of the filter housing with a garden hose.
  2. Carefully replace cartridge element over the tie rod and into the filter body, being sure that the cartridge seats evenly on the hub in the bottom of the filter body.
  3. place cover or caps on filter body. Be sure gasket or O-ring on dome is in place and lubricated with approved lubricant
  4. Tighten the locking knob or cap in a clockwise direction, hand tight only.
  5. Restart as per manufacturers instruction.

Cartridge Problems, Cures Most cartridge problems are caused by a dirty, clogged or abused element. Cleaning or replacing the element, as discussed earlier will correct these problems, with one exception: Oversized pumps, producing excessive flow rates and/or pressures may damage elements by flattening the pleats or folds; or breaking or splitting the end plates of the elements. Some cartridge filters have a valve device that allows some of the flow to bypass the filter cartridge when pressures are increased above normal. Check your owners manual to find out if you have one, and if there is any maintenance required or adjustments to be made.

Another possible complaint might be that a cartridge filter will not clean up algae. This is not true. Any of the three filter types will clear up algae, provided it is not in a live state. However, collecting algae is not one of the things that a cartridge filter does best. It takes longer for a cartridge filter to clear up an algae condition than sand or DE.

Cartridge filters are used widely as portable vacuuming systems and are a good choice for that job. Experience has shown that frequent cartridge cleaning or changing is necessary when cleaning up a dirty pool. Although it is possible to clean up very dirty pools through filtration, it is better, when possible, to vacuum heavy dirt to waste, then filter water until clean and polished.

Keep a spare cartridge and alternate their use, allowing the cartridge to dry between use. The drying process seems allow the cartridge material to breathe. Our experience shows that using this technique seems to increase the life of the cartridges.

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The oldest and most popular method of filtration is the sand filter. The high-rate sand filter was introduced more than thirty years ago and the only type of sand filter currently used for residential pools. They come in all sizes and shapes.
All sand filters share a couple of features, when in the filtration mode, water always flows from the top down and they all have some sort of lateral or underdrain designed with slots or holes to hold back sand while allowing the clean, water to pass through.
Outward appearance of filters and internal assemblies may vary, but, basically all sand filters operate the same way. Sand is added to the filter through a top valve or domed opening in the tank or by removing a cover. Vertical standpipes must be covered by a protective cap (a baggie or a coffee can will do) to keep from getting sand into the internal plumbing.The sand should be poured gently into the filter, being sure not to damage the laterals or underdrain. A good practice is to add enough water to cover the laterals or underdrain , because this will cushion the falling sand. On top-mount filters, be sure the lateral assembly is positioned properly into the center of the tank before pouring in the sand. Various guides are used to insure that the assembly is properly set, because improper seating of the vertical standpipe will prevent the valve from seating properly and may require that you remove all of the sand to reset it. Holding the top of the standpipe down while pouring the sand will prevent it from dislodging.
Once the proper amount of sand is added, the protective cap should be removed and the valve or dome mounted in place. Some valves thread into the top of the tank, others are held by clamp. All valves use some sort of O-ring as a seal. A liberal amount of O-ring lubricant should be applied to both the O-ring and the external threads to allow the valve to seat properly. On flange mount valves, this lubrication will allow adjustment once the clamp is semi-tightened. Be sure the lubricant is non-aggressive to plastic or rubber.
Sand filters use a special filter sand, normally .45 mm to .55, which is also known as pool grade #20 silica sand. The special sand has sharp edges that serve to separate particles, allowing filtration to take place. once the proper amount of sand has been added to the filter, it functions as the permanent dirt removing medium. Water from the pool, containing suspended dirt particles, is pumped through the piping system and is directed automatically by a filter control valve to the top of the tank. As the pool water is pumped down through the filter tank through the control valve and back to the pool through the piping system. his entire sequence is continuous and automatic and provide for total recirculation of the pool water. After a period of time, the accumulated dirt in the filter causes a resistance to flow, and the flow diminishes. This simply means that it is time to backwash (clean) the filter. With the control valve in the backwash position, the water flow is reversed through the filter so that it is directed to the bottom of the tank and up through the sand, thus flushing the previously trapped dirt and debris out the waste line. Once the filter is backwashed , the control valve is re-sequenced manually to -rinse- and then to -filter- to resume normal filtering. To prevent unnecessary strain on pipes and valves, always shut off the pump strainer and skimmer baskets regularly. Most Manufacturers require that new filters be started with the valve in "backwash" position for approximately two minutes. This is to remove any impurities or fine sand particles which normally exist in any new change of sand. The most common type of valve in use today is the 6-way multiport valve, which is manufactured by a number of companies. The one produced by Hayward is the most widely used and is the Vari-flo TM series. Following are the various positions and their functions.
FILTER- This is the valve position for normal filtration and is also the one used for normal vacuuming.
BACKWASH- Used for cleaning when the filter pressure gauge rises 6 to 8 pounds above the normal clean pressure, stop the pump and change the valve position to backwash . Start pump and backwash until water runs clear. This takes two minutes or less depending on dirt accumulation.
RINSE- After backwashing, with pump off, set valve to Rinse. Start pump and operate 30 seconds to 1 minute. This assures that all dirty water from backwashing is rinsed of of the filter to waste, preventing possible return to the pool. Stop pump and set valve to filter, and start pump for normal filtering.
WASTE- Used to bypass filter for draining or lowering the water level and for vacuuming heavy debris directly to waste.
RECIRCULATE- Water is circulated through the plumbing and valve, but bypasses the filter tank.
CLOSED- Shuts off flow from pump to filter. Do not shut off pump with running.


  • Filter in need of backwashing
  • Check skimmer and pump strainer baskets for debris
  • Check for clogged or restricted suction or return line
  • Check for a leak in suction lines. Any bubbles back to the pool confirm that the leak is on suction side of the pump
  • Laterals or underdrain may be clogged
  • Algae Superchlorinate to 30 ppm
  • Using Calcium based chemicals
  • Surface of sand bed crusted or caked. Remove 1" old the sand bed
  • An excess of oils and dirt cause mud balls in the sand. (Replace sand)
  • Filter not being run long enough
  • Chemicals out of balance
  • Valve not in filter position
  • Pump could be hooked up wrong.

If water doesn't clear after running filter 24 hours, you probably have contaminants too fine for the sand filter. Since sand filters only filter to about 30 microns you will need to provide something that will help filter finer materials. We recommend SPARKLE SANDAID.
Do Not Backwash too often. Wait until the pressure reading is 6-8 pounds above normal. Sand should be changed at least every other year.

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Some Common Sense Things To Know and Remember

Read all labels carefully before using -- Keep all chemicals out of the reach of children -- Handle all chemicals with care -- Don't ever mix chemicals together -- Always add chemical to water, Never add water to chemicals -- Always store chemicals in cool dry place -- Do Not reuse any empty chemical containers -- Use a reliable test kit and replace reagents every year -- Add chemicals in early morning or late evening when the sun is low -- Use a clean dry scoop for granular chemicals and spread over a wide are of water's surface, Sprinkle close to the water so as wind will not blow them in your face -- When dispensing liquids hold the container close to the surface to minimize splash -- Wash hands with soap and water after using chemicals -- Do Not prepare chemicals in your house or any other closed building.

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To Calculate average depth, measure water in the deep area and the shallow area then divide by 2.

Depth 1_____ + Depth 2 ______ = ______ / 2 =

__________ AVERAGE DEPTH

To calculate a rectangle, multiply length X width X
average depth X 7.5 = gallons

Length _____ x Width _____ x Avg. Depth ____ x 7.5 =

__________ TOTAL GALLONS

To calculate a round pool, multiply diameter X diameter X average depth X 5.9 = gallons

Diameter _____x Diameter _____x Avg. Depth x 5.9 =

__________ TOTAL GALLONS

To calculate an oval pool, multiply length X width X average depth X6.7 = gallons

Length _____x Width ______ x Avg. Depth x 6.7 =

__________ TOTAL GALLONS

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1997 Leisure Time Pools Inc -Bob Hayes
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