Hot Tub Chemical Dosing Calculator
Calculate chlorine, pH adjuster, and alkalinity doses for your hot tub volume.
Hot Tub Water Chemistry
Three numbers matter: Chlorine: 1-3 ppm (sanitizer — kills bacteria). pH: 7.2-7.6 (comfort and sanitizer effectiveness). Alkalinity: 80-120 ppm (pH stability). Test water 2-3 times per week with test strips. Adjust chlorine after every use. The most common mistake: letting chlorine drop to 0 between uses — bacteria multiply rapidly in warm water.
Common Hot Tub Problems
Cloudy water: Usually low sanitizer. Shock the tub and increase chlorine. Foamy water: Body oils, lotions, detergent residue. Use an anti-foam product and shower before entering. Strong chlorine smell: Paradoxically means NOT ENOUGH chlorine — the smell is chloramines (combined chlorine). Shock to break them down. Green water: Algae — shock heavily and run jets with cover off.
The #1 hot tub health risk is not chemicals — it is Pseudomonas folliculitis ("hot tub rash") from inadequate sanitization. Maintaining 1-3 ppm chlorine eliminates this risk. The bacteria grows rapidly in warm water (104°F) with low sanitizer — even a few hours at 0 ppm chlorine can cause an outbreak.
