Hot Tub Chemical Calculator

How It Works

Hot tub chemistry differs from pool chemistry in important ways. The higher water temperature (100-104 degrees F) makes sanitizer deplete much faster, so hot tubs need higher sanitizer levels. Bromine is preferred over chlorine for hot tubs because it remains effective at higher temperatures and produces less odor. Target 3-5 ppm for bromine or 1-3 ppm for chlorine. Hot tub pH tends to drift more because of the smaller water volume and body oils from soakers — test before every use. Shock your hot tub weekly with non-chlorine oxidizer (MPS) to break down organic contaminants. Replace the water entirely every 3-4 months depending on usage.