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Glossary
Pool and Spa Equipment terms, explained
Short, plain definitions of the words you'll see on product pages and spec sheets. Each one links to a guide when there's more to know.
A
- Average depth
- Shallow and deep end depths added and divided by two. Read the guide →
B
- Backwash
- Reversing flow through a sand or DE filter to flush trapped dirt. Read the guide →
- BTU
- British thermal unit, used to rate heater output per hour. Read the guide →
C
- Combined chlorine
- Chlorine bound to contaminants, which causes odor and irritation. Read the guide →
- COP
- Coefficient of performance, a heat pump's heat output per unit of electricity. Read the guide →
- CYA
- Cyanuric acid, a stabilizer that protects chlorine from sunlight. Read the guide →
D
- DE
- Diatomaceous earth, a fine powder used as filter media. Read the guide →
F
- FAS-DPD
- An accurate titration test for free and combined chlorine. Read the guide →
- Free chlorine
- Chlorine available to sanitize the water. Read the guide →
G
- GPM
- Gallons per minute of water flow through the pump and filter. Read the guide →
S
- Salt cell
- The part of a salt system that turns dissolved salt into chlorine. Read the guide →
T
- Total alkalinity
- The water's ability to resist pH changes. Read the guide →
- Turnover
- The time it takes the pump to circulate the pool's full volume once. Read the guide →