Testing Bromine


Active member
Sep 10, 2010
Hi all,

I read the sticky on bromine but have some confusion. The sticky says you can use regular bleach as an activator when you have sodium bromide in the water, but every thing I read and the pool stores say you can not mix bromine and chlorine. I am using the bromine tablets and testing with the TFT100 DPD and R871 reagent, if my bromine needs to be at 5, does that mean 10 drops on the test or half that ? as bromine = 2.2 x chlorine. Also can I test for sodium bromide reserve?



TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
The DPD reacts with any halogen - chlorine or bromine. It can not distinguish between them. So you must assume that what you are measuring is sanitizing bromine and use the appropriate scaling factor.

There’s is no way to practically test for the reduced bromide anion.

You absolutely can use chlorine bleach to activate the bromide. Chlorine oxidizes bromide into bromine. The tablets you are using are BCDMH (bromo-chloro-dimethyl hydantoin) so they carry the chlorine with them. When you add them to water, the chlorine comes off and actives the bromine. You’ll want to be careful with tablets as they are acidic and will lower pH and TA over time.