FAS-DPD testing with bromine

[waste]

Chemgeek wrote

Note that the test is measuring Total Bromine and there is no need for the R-0003 reagent. Combined Bromine is automatically measured in the first part of the test since monobromamine is in equilibrium with a more reactive monobromammonium ion that reacts with the dye in the test. It is this reactivity that makes the combined bromine still effective as a disinfectant (though monobromamine can smell if it gets high enough in concentration).

I've been using my TF100 all season on our indoor pool (not spa) and usually have to add another drop of the R 0871 after adding the R0003, so I include the last drop into my total bromine. I almost always get a little pink from adding the 5 drops of R0003.

Am I doing something wrong to get a result out of the R0003?

 

[AClogston]

Do you use MPS shock in this pool?

MPS will give a false high CC reading. I had to buy the special Taylor FAS-DPD kit because of this.

 

[waste]

Hey Al

As a general rule, I don't shock my pools - because I don't have to

However, my predecessor used to use it, last year - would it stay in the water (70% changed to start the pool this spring) that long?? [also, sometimes I don't get the cc (cb) reading]

Thanks for all replies

 

[CaOCl2]

What you're seeing is combined chlorine - some formulations of bromine include chlorine, first the chlorine sacrifices itself to oxidize the bromide ions into hypobromous acid. Then whatever chlorine is left combines with any organics and thus reacts with the R-0003 as combined chlorine. Combined bromine and free bromine have similar oxidizing capabilities that why you test for "total bromine".

 

[chem geek]

It's also possible for it to be an organic combined bromine (rather than the inorganic monobromamine) in which case I wouldn't count that as far as being bromine that you want since it is probably not a disinfectant. Unless that was rather high, I wouldn't worry about it.

 

[waste]

Thanks guys! :bowdown:

Sorry for the delay but.. things have been a little crazy at work the past couple of weeks - I've had to take on responsibilities that aren't in my job description (haven't we all, at one point or another :lol

Again, THANK YOU!!