AFO (Aquatics Facilitator Operator) Glossary EXAM QUESTIONS AND VE
FIED SOLUTIONS |ELABORATED &DETAILED ANSWERS!! AFO (Aquatics Fa
itator Operator) Glossary 2025
1. Acid A commonly use chemical compound dosed into swimming
pools that releases hydrogen ions in water thereby lowering
pH
2. Algae a simple nuisance plant life that colonizes in water under favor-
able conditions
3. Alkalinity A measure of the pH-buffering capacity of water
4. Aluminum Sulfate Alum; a flocculating agent frequently used as a supplement in
rapid sand filters only!
5. Ammonia (NH3) A chemical compound of hydrogen and nitrogen that combines
with free chlorine in pools to form chloramines, or combined
chlorine.
6. Automation Electronic equipment that senses water variables (primarliy
chlorine, ORP, temperature, and pH) and controls chemical
feeder or heater systems to maintain desired levels.
7. Backwash The process of cleaning a swimming pool filter by reversing the
flow of water through it.
8. Balance In pools, use to refer to a condition of the water that is neither
scaling nore aggressive/corrosive.
9. Basic Opposite of acidic, a pH condition above 7.
10. Bleach (NaCIO) Sodium hypochlorite, usually 12% strength, "liquid chlorine"
for pool use.
11. Body Coat (Body Feed)
, AFO (Aquatics Facilitator Operator) Glossary EXAM QUESTIONS AND VE
FIED SOLUTIONS |ELABORATED &DETAILED ANSWERS!! AFO (Aquatics Fa
itator Operator) Glossary 2025
Biatomaceous earth contimuously added to filter elements
during the course of a filter run to help maintain filter efficacy
and extend filter runs.
12. Breakpoint (Chlorination) The point in a rising chlorine residual at which the concen-
tration 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.
13. Bromine (Br2) 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.
14. Calcification (see also Scale) Formation of calcium carbonate on walls of pools or pipes, or
in a filter or heater, due to precipitation of calcium carbonate.
15. Calcium Hypochlorite Compound of chlorine and calcium used in white granular or
{Ca(CIO)2} tablet form as a disinfectant in pools. Typically, 65% chlorine by
weight and a pH of ~11 in water.
16. Calcium Saturation Index Derived from the Langelier Index, for determining water's ten-
(CSI) dency to scale or be aggressive. Sometimes known at the LSI
or SI.
17. Carbon Dioxide (CO2) 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.
18. Caustic Soda (NaOH) See "Sodium Hydroxide"
FIED SOLUTIONS |ELABORATED &DETAILED ANSWERS!! AFO (Aquatics Fa
itator Operator) Glossary 2025
1. Acid A commonly use chemical compound dosed into swimming
pools that releases hydrogen ions in water thereby lowering
pH
2. Algae a simple nuisance plant life that colonizes in water under favor-
able conditions
3. Alkalinity A measure of the pH-buffering capacity of water
4. Aluminum Sulfate Alum; a flocculating agent frequently used as a supplement in
rapid sand filters only!
5. Ammonia (NH3) A chemical compound of hydrogen and nitrogen that combines
with free chlorine in pools to form chloramines, or combined
chlorine.
6. Automation Electronic equipment that senses water variables (primarliy
chlorine, ORP, temperature, and pH) and controls chemical
feeder or heater systems to maintain desired levels.
7. Backwash The process of cleaning a swimming pool filter by reversing the
flow of water through it.
8. Balance In pools, use to refer to a condition of the water that is neither
scaling nore aggressive/corrosive.
9. Basic Opposite of acidic, a pH condition above 7.
10. Bleach (NaCIO) Sodium hypochlorite, usually 12% strength, "liquid chlorine"
for pool use.
11. Body Coat (Body Feed)
, AFO (Aquatics Facilitator Operator) Glossary EXAM QUESTIONS AND VE
FIED SOLUTIONS |ELABORATED &DETAILED ANSWERS!! AFO (Aquatics Fa
itator Operator) Glossary 2025
Biatomaceous earth contimuously added to filter elements
during the course of a filter run to help maintain filter efficacy
and extend filter runs.
12. Breakpoint (Chlorination) The point in a rising chlorine residual at which the concen-
tration 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.
13. Bromine (Br2) 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.
14. Calcification (see also Scale) Formation of calcium carbonate on walls of pools or pipes, or
in a filter or heater, due to precipitation of calcium carbonate.
15. Calcium Hypochlorite Compound of chlorine and calcium used in white granular or
{Ca(CIO)2} tablet form as a disinfectant in pools. Typically, 65% chlorine by
weight and a pH of ~11 in water.
16. Calcium Saturation Index Derived from the Langelier Index, for determining water's ten-
(CSI) dency to scale or be aggressive. Sometimes known at the LSI
or SI.
17. Carbon Dioxide (CO2) 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.
18. Caustic Soda (NaOH) See "Sodium Hydroxide"
