Chlorine Loss Calculator
Hot Tub Size
Enter the total capacity of your hot tub in gallons. Check your manual or measure dimensions for accuracy.
Water Temperature
Higher temperatures accelerate chlorine depletion. Normal hot tub range is 100-104°F.
People Per Day
More bathers introduce more contaminants that consume chlorine.
Cover Usage
Covers reduce UV exposure, which is a major cause of chlorine loss.
Select cover usage
Yes, Always
Sometimes
No Cover
pH Level
Ideal pH range is 7.2-7.8. Outside this range, chlorine becomes less effective.
Cyanuric Acid Level
Stabilizer helps protect chlorine from UV degradation. Ideal range for hot tubs is 30-50 ppm. You need a water test kit to measure this value.
Cyanuric acid (CYA) is a stabilizer that protects chlorine from UV rays. You'll need a test kit to measure this – most pool/spa test strips include a CYA test. If you don't know your level, enter 0 for unstabilized water or 30 for recently balanced water.
Signs of Biofilm
Biofilm is a slippery film that can form on surfaces and consumes large amounts of chlorine.
Select option
No
Yes
Signs of biofilm include: slimy surfaces in the tub, cloudy water that returns quickly after clearing, foam that persists despite treatment, unpleasant smell, or rapid chlorine depletion. Biofilm is a colony of bacteria that forms a protective layer on surfaces.
Calculate Chlorine Loss