Still Bromine Confused

[williebluffu]

I have read and read and read...From Pool School to how to use Bromine in my spa to how can I test Bromine levels in my spa...Everytime I think I have it down I read something again and think wow...maybe I dont.

I have a 350 gal (I think) South Seas Spa. We used to also have above ground pool and I used the BBB in both. Since moving we no longer have the pool...this year after much reading I decided the Bromine Hot tub made more sense.

I have A tf-100 Test kit. This morning I tested my spa and readings were as follows.

Br-10- (using the basic K-1000 kit from Taylor)
PH 7.2 (It has dropped a bit since last weeks testing.
FC-3 (using the TF-100 FAS/DPD) Here is where I am a bit confused. Do I now multiply that number by 2.2 making my FC 6.6?
My CC is .5 (maybe...i got a little tint but one drop and it was clear)
Makes my TC- 3.5
My TA is low at 20.
I went ahead and tested for CYA but- Its my understanding that CYA is not an issue for Bromine Spas....and I didnt see any CYA in the test.

In the big thread "How do I use Bromine in my spa" it is recomended to purchase the Taylor K-2106. If thats what I need to do I will do but....Is most of this kit the same as my TF-100 kit? Sould I but just selected regents/tests?

Sorry for all the questions...

 

[pooldv]

Welcome to TFP!

The tf-100 is fine. Multiply each drop of the FAS-DPD test by 1.25 for bromine or 0.5 for FC when using a 10ml sample. Raise your TA to 50 using baking soda.

 

[JoyfulNoise]

The FAS-DPD reagents are measuring the halogen level in the water - any chlorine (which should be minimal) + bromine. Assuming you have the proper bromide bank established in your water, then there will be zero chlorine because all of the chlorine will activate the bromide into bromine. So all of your measurements are measuring bromine levels.

The K-2106 is just a test kit designed for bromine spas. So it eliminates the CYA test since that is not important and just gives you the pH, TA, CH and FAS-DPD. The problem is, the K-2106 uses a slightly different formulation of the FAS titrating reagent - R-0872 which then equates to 0.5ppm/drop (for the 25mL water sample) or 1.25ppm/drop (for 10mL water sample). The R-0871 that comes with your TF-100 might give you a slightly different value. The R-0870 DPD powder is the same in both, so you could just buy the R-0872 FAS titrating reagent to complete your kit.

The thing to remember is this - DPD does not distinguish between chlorine, bromine or iodine. All of those halogens cause the DPD dye to turn pink.