Using Pool Math to add Chlorine to Bromine pool

#1
Recently switched to bromine since my swim spa can sit unused for up to a week while traveling. Was using MPS as an oxidizer but recently switched to bleach. Trying to calculate how much bleach to use to raise bromine levels. I know that I calculate bromine levels by calculating my free chlorine results by 2.25, but how do I convert the amount of chlorine to add to raise bromine levels.

For example, for my 1500 gallon swim spa, pool math tells me 2.2 oz of 8.25% bleach will raise my free chlorine level by 1. Should I expect my bromine level to go up by 1, or 2.25, or some other number?

Thanks.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,680
Tucson, AZ
#2
1ppm of chlorine will raise the bromine levels by 2.25ppm assuming all of the chlorine oxidizes the bromide in the water. Chlorine will oxidize bromide and bather waste at different rates and so some chlorine you add could go to destroying bather waste and not regenerating bromine. Thus there will be some trial and error to the process.

DO note that some test kits just round down when they report total bromine levels where they equate 1ppm free chlorine to 2ppm bromine.