Hot tub chemistry calculator
PROBromine or dichlor dose for a spa.
Short answer: Dichlor oz = (gal/10k) × 0.23 × ppm. Bromine similar (× 0.25). 400 gal × 4 ppm dichlor = 0.04 oz (~1 gram). Enter your measurements above and the hot tub chemistry calculator returns the quantity, unit conversions and an estimated cost instantly, in imperial or metric — no sign-up needed.
What do you need to measure?
What is the answer?
Dichlor
0.04 oz
Sodium bromide
0.04 oz
How does the hot tub chemistry calculator work?
Dichlor oz = (gal/10k) × 0.23 × ppm. Bromine similar (× 0.25).
What does a worked example look like?
400 gal × 4 ppm dichlor = 0.04 oz (~1 gram).
What do people ask most?
›Bromine vs chlorine?
Bromine handles hot water better and irritates less.
Which pool calculator should you use next?
Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.