The purpose of the filter is to remove foreign material from the water. These materials consist mainly of airborne dirt and leaves, organic matter introduced by bathers, and organisms such as bacteria and algae. Swimming pool filtration is a mechanical straining or entrapping process. A well-designed and properly operated filter will remove virtually all of the insoluble suspended matter in the water producing a sparkling clean condition. It must be recognized that a filter does not destroy living organisms such as algae and bacteria. This is accomplished by the use of chemicals. 

The length of time the filter must be operated to produce the desired clarity will vary with several conditions, some of the most significant being:

  1. Number of bathers
  2. Temperature
  3. Sunlight
  4. Degree of chlorination (covered in Pool Chemistry Section)
  5. Proper pH control (covered in Pool Chemistry Section)
  6. Exposure to airborne contamination

There are several types of filters that may be used on swimming pools. The most satisfactory are described below: 


Cartridge filters consist of a removable-replaceable filter element. There are two basic types of cartridges, namely depth and surface. Dept cartridges consist of a thick layer of fiberous materials graded and blended to provide thousands of tiny crevices to trap dirt. Surface cartridges are made by pleating specially compounded paper or synthetic fabric to provide a large area of fiber surface in a relatively small volume. The fabric is made with controlled porosity to screen out dirt and other foreign matter as the water passes through. When the cartridge becomes clogged with dirt, it is removed, washed, and returned to the filter. Successive use of the cartridge leaves a residue of dirt so that after several cleanings the cartridge is discarded and replaced with a new one. Having a spare cartridge to alternate in use is advisable.


Sand filters are designed to operate at various flow rates depending on their tank and internal component configurations.  With correct distribution and flow of water, the carefully sized sand bed will trap dirt throughout its depth thus providing a fairly large dirt retention volume. Without correct flow distribution, dirt may be driven through the sand without performing its intended function. Cleaning of the sand bed is done by passing water at high velocity in reverse (up flow) through the sand. This causes a scrubbing action of the sand freeing the dirt, which is carried to waste.


Due to the fineness of the diatomaceous earth particles, a high degree of filtration efficiency may be obtained with this type of filter. A precoat layer of diatomaceous earth (filter aid) is applied hydraulically upon the surfaces of the filter elements or other filtration surfaces. Due to the minute pores created by this precoat layer, very small particles are screened out as the water passes through the filter, thus producing a highly polished sparkling condition in the water. After the filter has removed its capacity of dirt from the water and the flow has reduced appreciably, the clogged filter aid is removed by one of several means and discarded to waste. 


Surface cleaning is accomplished by automatic surface skimming and manual hand skimming.


The automatic surface skimmer is a device which is attached to the pump intake line and which rests on the pool surface. The continual flow of water from the surface of the pool through the skimmer removes floating debris such as oils, leaves, and other airborne materials before they settle to the bottom of the pool. A floating weir in the skimmer automatically adjusts for variations in the pool water level. The surface skimmer also serves as a convenient means of introducing filter aid for precoating a diatomaceous earth filter. NEVER ADD CHEMICALS THROUGH SKIMMER.



1.      AUTOMATIC CIRCULAR TYPE SKIMMER – This design, attached to the suction line contains a floating weir that permits introduction of water from all directions, thus increasing the skimmer effectiveness. A self-contained strainer traps large particles such as leaves and twigs to prevent their entry into the pump.

2.      THRU-THE-WALL SKIMMER – Attached to the outer side of the pool wall, this permanently installed skimmer collects surface water without having any projections within the pool that might interfere with bathers. It provides a more positive control of skimming being rigidly mounted. A built-in strainer basket to collect leaves and other debris is easily removed for cleaning. 

3.      HAND SKIMMER – The pool surface may be skimmed by hand with the leaf skimmer. It consists of a dished screen net supported by a rigid ring to which a handle is attached. By attaching an extension handle, leaves may also be removed from the bottom of the pool. 


1.      DIRECT SUCTION CLEANER – This type of cleaner is operated from flow produced by the filter pump.  A vacuum cleaner hose is connected between the cleaner head and the pump intake line. This method produces an efficient means of cleaning. Sediment from the bottom of the pool is drawn through the cleaner head to the filter where the dirt is removed and the clear water is returned to the pool without waste. The cleaner head is moved systematically over the floor surface to remove all sediment. For most efficient operation, the filter and pump strainer should be clean before operating the vacuum leaner. Care should be used when operating vacuum cleaner in cove area. Some vacuum heads can puncture the liner in this area. 

2.      JET VACUUM CLEANER – The operation of a jet-type cleaner requires the use of city water pressure which is conducted to the cleaner head through a garden hose. By means of an ejector jet built into the cleaner, a vacuum is created which picks up sediment from the pool floor and deposits it in a porous bag attached to the cleaner.


The suction from a pool drain can be so powerful that it can hold an adult under water, but most incidents involve children. The body can become sealed against the drain or hair can be pulled in and tangled. Missing or broken drain covers are a major reason many entrapment incidents occur. Pool and spa owners can consider installing a Safety Vacuum Release System (SVRS), which detects when a drain is blocked and automatically shuts off the pool pump or interrupts the water circulation to prevent an entrapment. 

Every time you use a pool or spa, inspect it for entrapment hazards. Check to make sure appropriate drain covers are in place and undamaged.


Keeping your pool water in balance is a key step in quality pool care. When your pool water is balanced then pool care is easy. but when it becomes unbalanced, problems can and will arise.  Pool Water Balance takes into account pH, Calcium and TA or Total Alkalinity

The table below applies to all pools.

Correct  Levels Ensure:

Bacteria fighting power of chemicals will be at their peak

You will not see a corrosive build up on pools or parts

Minimal Pool and Eye Irritations

To keep your pool balanced, test it and then add what is necessary.

For pH

If pH is low add a pH Plus Product  Like Pool Life Plus

If pH is High add a pH Minus Product Like Pool Life Minus

For Calcium Hardness

If Calcium is low add a water hardener agent

if Calcium is High add a sequestering agent

For Total Alkalinity

If Alkalinity is Too high, add an Alkalinity Decrease

If Alkalinity is Too low, add an Alkalinity Increaser

CPSC's Safety Tips For Preventing Electrocutions In and Around the Pool

  • Know where all the electrical switches and circuit breakers for pool equipment and lights are located and how to turn them off in an emergency.
  • Refrain from swimming before, during, or after thunderstorms.
  • Have an electrician who is qualified in pool and spa repairs inspect and upgrade your pool, spa or hot tub in accordance with applicable local codes and the National Electrical Code (NEC).
  • Ensure that all electrical wires and junction boxes are at least five feet away from water, as required by the NEC.
  • Protect swimmers from injury by following the NEC requirements for installing GFCIs:
    • on underwater lighting circuits operating at 120-volts (CPSC recommends GFCIs for circuits that are 15 volts or greater);
    • on pumps and electrical equipment used with pools, spas and hot tubs, including heaters close to the pool and operated on 240 volt circuits;
    • on electrical circuits around pools, spas, and hot tubs;
    • on all outdoor receptacles and receptacles within 20 feet of the water's edge to protect people from injury.
  • Test GFCIs monthly to assure continued protection. Infrequently used and portable or cord-connected GFCIs should be tested before each day's use. To test a GFCI:
    • Plug a nightlight into the outlet and turn the nightlight on.
    • Press the "TEST" button. Did the light go out? If not, replace the GFCI or have it inspected by an electrician.
    • Press the "RESET" button. Did the light come back on? If not, replace the GFCI.
    • Wear shoes while conducting the test, especially if outdoors or standing on wet ground.
  • Use battery-operated appliances instead of cord-connected appliances in and around a pool, spa, or hot tub.
  • Post an emergency plan within clear view of those using the pool.
  • Ensure that overhead power lines and junction boxes are safely positioned when installing a new pool, hot tub or spa.

Consumer Product Safety Commission

"Spas, Hot Tubs, and Whirlpools"

The U.S. Consumer Product Safety Commission (CPSC) helped develop standards to prevent hair entanglement and body part entrapment in spas, hot tubs, and whirlpools. These standards should help prevent deaths and injuries. Consumers should fix their old spas, hot tubs, and whirlpools with new, safer drain covers. CPSC warns about these hazards:

  • Drownings -- The main hazard from hot tubs and spas is the same as that from pools - drowning. Since 1990, CPSC has reports of more than 800 deaths in spas and hot tubs. About one-fifth of those were drownings to children under age five. Consumers should keep a locked safety cover on the spa whenever it is not in use and keep children away unless there is constant adult supervision.
  • Hair Entanglement -- Since 1990, CPSC has reports of 43 incidents (including 12 deaths) in which people's hair was sucked into the suction fitting of a spa, hot tub, or whirlpool, causing the victim's head to be held under water. Hair entanglement occurs when a bather's hair becomes entangled in a drain cover as the water and hair are drawn through the drain. In some incidents, children were playing a "hold your breath the longest" game. Permitting their long hair to be sucked into the drain. CPSC helped develop a voluntary standard for drain covers that helps reduce the risk of hair entrapment. Consumers should be sure they have new drain covers that meet this standard. If you are not sure, call a pool or spa professional to check the spa. Never allow a child to play in a way that could permit the child's hair to come near the drain cover. If a drain cover is missing or broken, shut down the spa until the cover is replaced.
  • Body part Entrapment -- CPSC knows of 74 incidents since 1990 in which parts of the body have been entrapped by the strong suction of the drain of pools, wad-ing pools, spas, and hot tubs. Of these, two resulted in disembowelment and 13 other people died. CPSC helped develop a standard requiring dome-shaped drain outlets and two outlets for each pump. This reduces the powerful suction if one drain is blocked. Consumers with older spas should have new drain covers installed and may want to consider getting a spa with two drains.

  • Hot Tub Temperatures -- CPSC knows of several deaths from extremely hot water (approximately 110 degrees Fahrenheit) in a spa. High temperatures can cause drowsiness which may lead to unconsciousness, resulting in drowning. In addition, raised body temperature can lead to heat stroke and death. In 1987, CPSC helped develop requirements for temperature controls to make sure that spa water temperatures never exceed 104 degrees Fahrenheit. Pregnant women and young children should not use a spa before consulting with a physician.

CPSC recommends these safety precautions when using a hot tub, spa, or whirlpool: 

1. Always use a locked safety cover when the spa is not in use and keep young children away from spas or hot tubs unless there is constant adult supervision.

2. Make sure the spa has the dual drains and drain covers required by current safety standards. 

3. Regularly have a professional check your spa or hot tub and make sure it is in good, safe working condition, and that drain covers are in place and not cracked or missing. Check the drain covers yourself throughout the year.

4. Know where the cut-off switch for your pump is so you can turn it off in an emergency. 

5. Be aware that consuming alcohol while using a spa could lead to drowning.

6. Keep the temperature of the water in the spa at 104 degrees Fahrenheit or below.

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This document is in the public domain. It may be reproduced without change in part or whole by an individual or organization without permission. If it is reproduced, however, the Commission would appreciate knowing how it is used. Write the U.S. Consumer Product Safety Commission, Office of Information and Public Affairs, 4330 East West Highway, Bethesda, MD 20814 or send an e-mail to