AFO (Aquatics Facilitator Operator) Glossary Exam Complete Test , Practice
Questions, Verified Answer Key, and Study Guide for (Latest 2026 Edition)
Acid - (answer)A commonly use chemical compound dosed into swimming pools that releases hydrogen
ions in water thereby lowering pH
Algae - (answer)a simple nuisance plant life that colonizes in water under favorable conditions
Alkalinity - (answer)A measure of the pH-buffering capacity of water
Aluminum Sulfate - (answer)Alum; a flocculating agent frequently used as a supplement in rapid sand
filters only!
Ammonia (NH3) - (answer)A chemical compound of hydrogen and nitrogen that combines with free
chlorine in pools to form chloramines, or combined chlorine.
Automation - (answer)Electronic equipment that senses water variables (primarliy chlorine, ORP,
temperature, and pH) and controls chemical feeder or heater systems to maintain desired levels.
Backwash - (answer)The process of cleaning a swimming pool filter by reversing the flow of water
through it.
Balance - (answer)In pools, use to refer to a condition of the water that is neither scaling nore
aggressive/corrosive.
Basic - (answer)Opposite of acidic, a pH condition above 7.
Bleach (NaCIO) - (answer)Sodium hypochlorite, usually 12% strength, "liquid chlorine" for pool use.
Body Coat (Body Feed) - (answer)Biatomaceous earth contimuously added to filter elements during the
course of a filter run to help maintain filter efficacy and extend filter runs.
, AFO (Aquatics Facilitator Operator) Glossary Exam Complete Test , Practice
Questions, Verified Answer Key, and Study Guide for (Latest 2026 Edition)
Breakpoint (Chlorination) - (answer)The point in a rising chlorine residual at which the concentration of
available chlorine becomes great enough to oxidize most organiz matter, chloramines, and ammonia
compounds in a pool. Chlorine added thereafter will be in the uncombined, or free, state.
Bromine (Br2) - (answer)a heavy, dark-reddish-brown liquid in the same chemical family as chlorine gas.
It is sometimes used as a bactericide in pools, usually in a solid-compound or salt form.
Calcification (see also Scale) - (answer)Formation of calcium carbonate on walls of pools or pipes, or in a
filter or heater, due to precipitation of calcium carbonate.
Calcium Hypochlorite {Ca(CIO)2} - (answer)Compound of chlorine and calcium used in white granular or
tablet form as a disinfectant in pools. Typically, 65% chlorine by weight and a pH of ~11 in water.
Calcium Saturation Index (CSI) - (answer)Derived from the Langelier Index, for determining water's
tendency to scale or be aggressive. Sometimes known at the LSI or SI.
Carbon Dioxide (CO2) - (answer)common gas found in air; exhaled in human breath. Forms of carbonic
acid when dissolved in water and contributes to bicarbonate alkalinity when added to water, thereby
lowering pH and raising alkalinity.
Caustic Soda (NaOH) - (answer)See "Sodium Hydroxide"
Channelization - (answer)The undesirable process whereby filter sand is permeated by tubes or channels
of calcified or oily material, allowing water to pass freely through the filter.
Chemical Feeder - (answer)A device designed for automatic addition of chemicals to swimming pool
water.
Questions, Verified Answer Key, and Study Guide for (Latest 2026 Edition)
Acid - (answer)A commonly use chemical compound dosed into swimming pools that releases hydrogen
ions in water thereby lowering pH
Algae - (answer)a simple nuisance plant life that colonizes in water under favorable conditions
Alkalinity - (answer)A measure of the pH-buffering capacity of water
Aluminum Sulfate - (answer)Alum; a flocculating agent frequently used as a supplement in rapid sand
filters only!
Ammonia (NH3) - (answer)A chemical compound of hydrogen and nitrogen that combines with free
chlorine in pools to form chloramines, or combined chlorine.
Automation - (answer)Electronic equipment that senses water variables (primarliy chlorine, ORP,
temperature, and pH) and controls chemical feeder or heater systems to maintain desired levels.
Backwash - (answer)The process of cleaning a swimming pool filter by reversing the flow of water
through it.
Balance - (answer)In pools, use to refer to a condition of the water that is neither scaling nore
aggressive/corrosive.
Basic - (answer)Opposite of acidic, a pH condition above 7.
Bleach (NaCIO) - (answer)Sodium hypochlorite, usually 12% strength, "liquid chlorine" for pool use.
Body Coat (Body Feed) - (answer)Biatomaceous earth contimuously added to filter elements during the
course of a filter run to help maintain filter efficacy and extend filter runs.
, AFO (Aquatics Facilitator Operator) Glossary Exam Complete Test , Practice
Questions, Verified Answer Key, and Study Guide for (Latest 2026 Edition)
Breakpoint (Chlorination) - (answer)The point in a rising chlorine residual at which the concentration of
available chlorine becomes great enough to oxidize most organiz matter, chloramines, and ammonia
compounds in a pool. Chlorine added thereafter will be in the uncombined, or free, state.
Bromine (Br2) - (answer)a heavy, dark-reddish-brown liquid in the same chemical family as chlorine gas.
It is sometimes used as a bactericide in pools, usually in a solid-compound or salt form.
Calcification (see also Scale) - (answer)Formation of calcium carbonate on walls of pools or pipes, or in a
filter or heater, due to precipitation of calcium carbonate.
Calcium Hypochlorite {Ca(CIO)2} - (answer)Compound of chlorine and calcium used in white granular or
tablet form as a disinfectant in pools. Typically, 65% chlorine by weight and a pH of ~11 in water.
Calcium Saturation Index (CSI) - (answer)Derived from the Langelier Index, for determining water's
tendency to scale or be aggressive. Sometimes known at the LSI or SI.
Carbon Dioxide (CO2) - (answer)common gas found in air; exhaled in human breath. Forms of carbonic
acid when dissolved in water and contributes to bicarbonate alkalinity when added to water, thereby
lowering pH and raising alkalinity.
Caustic Soda (NaOH) - (answer)See "Sodium Hydroxide"
Channelization - (answer)The undesirable process whereby filter sand is permeated by tubes or channels
of calcified or oily material, allowing water to pass freely through the filter.
Chemical Feeder - (answer)A device designed for automatic addition of chemicals to swimming pool
water.
