How much bromine for your hot tub, by size

Bromine: a sodium bromide reserve in fresh water, activated with a small oxidizer dose and kept up with bromine tablets. Pick your tub size for a full table, or use the calculator for any volume.

Any other size

gal

Not sure? Find your tub’s volume.

ppm
ppm

Hot tubs: 4 to 6 ppm. Never soak above 8.

%

Add

0.45oz

of Non-chlorine shock (MPS 45%)

13 gabout 1¾ tsp by volume

Raises bromine from 1 ppm to 5 ppm in 400 gal, if the tub has a bromide reserve.

  • MPS reads as combined chlorine on DPD tests for about a day. Test CC the next morning.
  • Run the jets with the lid open and wait at least 15 minutes (20 after pH decreaser) before anyone gets in.
  • A small, measured dose of MPS or chlorine turns some of the bromide reserve into active bromine. Not a full shock.
  • No reserve (fresh water)? Build it first: switch “What you need” to new water.

Check the product label. Strengths vary by brand, so enter the % printed on yours. Add one chemical at a time, into the water, and never mix chemicals.

Save this test and get a reminder before your next soak.

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