How to Measure Sodium Bromide?

hotubbie

Member
May 17, 2020
22
Dallas
How does one measure the amount of Sodium Bromide (Bromide Reserve) in a hot tub? I see all the usual drop and strip tests for Bromine, but nothing yet for reserve Sodium Bromide. What I do see is when my Bromine levels are testing low and then I oxidize with MPS, the bromine measure increases - so it must be coming from a Bromide reserve. What I don't know is how much reserve is left before it is oxidized.

Thanks!
 

hotubbie

Member
May 17, 2020
22
Dallas
Bromine testing is like total chlorine. You cannot separate bromine from bromide in a test.
Thanks. Does this mean that if there is a bromide reserve in the water with no oxidation agent (MPS, Dichlor, Etc.) that there is no way to measure the sodium bromide levels - you can only measure the bromine levels? What I'm trying to find out is whether oxidation will create bromine to sanitize before I add the oxidizer (in this case MPS).
 

JamesW

TFP Expert
Mar 2, 2011
19,456
There's no easy way to measure bromide levels or any need to do so.

Once you add the initial amount of sodium bromide, the reserve stays in the water.

Any oxidizer will convert some of the bromide into bromine.

Ozone, chlorine or MPS will oxidize bromide into bromine.

Bromine is testable with the FASDPD test kit.
 
  • Like
Reactions: RDspaguy

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,430
NW Ohio
Sodium bromide shows up as just any other salt in the water. There's really no way to test for it. Not that there's too much of a need, you can't really overshoot a bromide bank since the excess will just remain in the water as a salt.
 
  • Like
Reactions: RDspaguy

hotubbie

Member
May 17, 2020
22
Dallas
Fantastic! That really helps. I'm thinking then that I'll just add a bit of sodium bromide along the way, then oxidize to enable the bromine level. If the bromine levels slow down after the oxidization, then I know more bromide is needed in the reserve.

As an alternative to this, maybe I should not be concerned about a bromide reserve and just regularly add brominating concentrate as needed and let the floater bromine tabs continue to feed...thoughts?