- A -

Acid Demand - The amount of acid needed to lower the pH to the correct level. [ More info...]

Algae - A collection of tiny plants that grow in the water, turning it green, black, yellow, or brown, while making the water feel slimy. [ More info...]

Algaecide - Anything that kills existing algae.

- B -

Bacteria - Single-celled microorganisms that can infest pool water and cause illness.

Backwash - Reverse flow of water through the filter to the drain, cleaning it and restoring good circulation and filtration.

Balanced Pool Water - Water that has the correct levels of pH, Total Alkalinity, Calcium Hardness and Stabilizer. Remember, it is possible that your water is within ideal ranges while still not being perfectly balanced. That's why six-week water analyses at your Sustain System Dealer are necessary. [ More info...]

- C -

Calcium Hardness - The measure of the amount of dissolved calcium in the water, which protects pool equipment and plaster finishes from corrosion. Ideal range is 200-800 ppm.

Calcium Hypochlorite - A powerful oxidizing chemical that cleans and sanitizes pool water.

Chloramines - Nitrogen compounds that form when the Free Available Chlorine combines with organic contaminants, such as perspiration and urine. Chloramines cause eye irritation and a strong odor.

Chlorinated Cyanurates (ISOs) - Also known as stabilized chlorine, trichlor or dichlor. ISOs are a family of pool care products that contain cyanuric acid, commonly known as stabilizer. Continued use of these products can lead to excessive cyanuric acid (stabilizer build-up) and corrosive water.

Chlorine - The most widely used chemical for sanitizing water. Found in calcium hypochlorite. A biocidal agent, chlorine is used to kill bacteria and algae found in pools.

Chlorine Demand - The amount of chlorine needed to establish a stable FAC residual after destroying algae, bacteria and other contaminants.

Chlorine Lock - Over-stabilization, often the result of continued use of trichlor tablets, which can cause chlorine to kill algae and bacteria at an undesirably slow rate. Sustain Chlorinating Tablets do not contain stabilizer, so they help to avoid this problem

Chlorine Residual - The chlorine levels remaining in the water after the chlorine demand has been satisfied. It’s the amount left to kill new bacteria and algae yet to enter the pool water.

Clarifier - A chemical that coagulates and neutralizes suspended particles in water, thus making them easier to remove by the filter.

Combined Available Chlorine - Total Available Chlorine minus Free Available Chlorine (TAC-FAC).

Copper - A metal that forms compounds, which cause blue-green water and black stains. Copper is the active ingredient in many algaecides. Sustain Pool Chemicals do not include a copper-based algaecide because of the risk of staining. Use a metal remover to rid water of copper. [ More info...]

Corrosion - The pitting and dissolving away of metal components including filter housings, pump housings, mechanical seals, heater elements, metal fixtures, plaster and tile grout. Low pH level, Total Alkalinity, and/or Calcium Hardness can cause this problem. [ More info...]

Cyanuric Acid (CYA) - s-triazinetrione, a chemical commonly referred to as stabilizer or conditioner that helps prevent the loss of Free Available Chlorine residual in direct sunlight. Ideal range is 30-50 ppm.

- F -

Filter Aid - A chemical that works in conjunction with the filter to help it remove fine particles more efficiently.

Flocculating Agent (also called coagulant) - A chemical that coagulates and neutralizes suspended particles in water, thus making them easier to remove.

Free Available Chlorine (FAC) - The portion of the total chlorine remaining in chlorinated water that will kill undesirable organisms. Recommended range is 1 to 3 ppm. Refer to Test Kit in this glossary for testing methods.

- I -

Iron - A metal, which forms compounds that can cause red/brown pool water and staining. [ More info...]

Isocyanuric Acid - See " Cyanuric Acid" or " Chlorinated Cyanurates".

- O -

Overstabilization - Condition that is caused by having too much stabilizer. See " Chlorine Lock".

- P -

pH - The acidity or basicity of pool water. Neutral is a pH of 7.0. Above 7.0 is basic; below is acidic. The recommended pH range is between 7.0 and 7.6, with 7.2-7.4 Being ideal. [ More info...]

PPM: Parts Per Million - The parts by weight of a chemical per million parts of water. For example, one pound of salt dissolved in one million pounds of water equals 1 ppm of salt.

- S -

Sanitizer - Primary chemical used to kill bacteria, germs, and other harmful microorganisms. Sustain 3-inch Chlorinating Tablets are a good example.

Scale - A precipitate that forms on surfaces in contact with water when the pH level, Total Alkalinity and/or Calcium Hardness are too high.[ More info...]

Settling Agent - See " Flocculating Agent".

Sequestering Agents - Chemicals that combine with dissolved metals to prevent water discoloration and pool staining.

Shock Treatment - The practice of adding larger amounts of chlorine to super-chlorinate water to destroy organic contaminants and restore water clarity. Shield Energizer Tablets and Sustain Shock Treatment are good examples.

Stabilizer – A common name for Cyanuric Acid (CYA) or s-triazinetrione. This chemical helps prevent the loss of Free Available Chlorine residual in direct sunlight. Ideal range is 30-50 ppm.

Superchlorination - Also called " Shock Treatment". The practice of adding larger amounts of chlorine to destroy organic contaminants and restore water clarity. Shield Energizer Tablets and Sustain Shock Treatment are good examples.

- T -

Test Kit - A tool to determine the amount of pH, chlorine, and other factors related to pool water balance. Three-Way Test Strips and DPD 2-Way Test Kits are good examples. Another common reagent for testing chlorine is OTO, which tests for Total Chlorine, not just free Available Chlorine. OTO test kits are NOT recommended for use with the Sustain System.

Total Alkalinity - Total Alkalinity buffers the water to prevent drastic pH fluctuations. Ideal range is 80-100 ppm.

Total Available Chlorine (TAC) - The sum of free and combined chlorines.

Total Dissolved Solids (TDS) - The amount of dissolved substances in water balance and may make it taste salty.

- W -

Water Balance - Water that has the correct levels of pH, Total Alkalinity, Calcium Hardness and Stabilizer. Remember, it is possible that your water is within ideal ranges while still not being perfectly balanced. That's why six-week water analyses at your Sustain System Dealer are necessary.

Winterizing - Preparing a semi-filled pool for the winter months, as opposed to draining. See the section entitled "Closing Your Pool".