Indoor Bromine --> Salt conversion question

[seilsel]

I am hoping that someone could explain the "once a bromine pool, always a bromine pool" adage a little further.

An indoor pool, drained one week ago and re-balanced. Bromine tablets are dissolving in a commercial-grade chemical dispenser. However, the bromide salts used to create a "bromine reserve" were not used.

My (very limited) understanding of traditional practice is that switching to salt/chlorine for sanitation would require draining the pool, because any chlorine generated by the cell would be converted to bromine.

1) Is that true?

2) If so, what is the downside to switching to salt/chlorine and having the chlorine that is generated converted to bromine?

Basically, do you really need to drain said indoor pool before converting from bromine tablets to a salt system?

Thanks folks.

 

[chem geek]

If you've only been using bromine tabs for a week and didn't add any bromide salts for a bromide bank, then I think you've probably got so little bromine/bromide in your pool that converting to a saltwater chlorine generator (SWG) could work without draining the pool. With so little bromide, the SWG will most likely produce chlorine, not bromine, but then that chlorine will convert any bromide into bromine. So that's where the pool stays a bromine pool.

However, with so little bromine/bromide, it will slowly outgas from the pool so over some time, perhaps a month or so, you could have it all removed and become a chlorine pool. This is speculation, however, and Ben Powell in this link says that the bromine won't get removed. The main problem with the tabs is the DMH that may act somewhat like CYA to bromine, though perhaps not until the DMH amount gets pretty high and in your case it won't be very high.

Sorry to be so wishy-washy on the answer, but I don't know if you'll be able to convert over, but then again it's not a disaster if the chlorine from the SWG converts bromide to bromine. Your water will still be sanitized and your test kit won't be able to tell the difference. The only real downside I can see would be that you'd have the bromine smell instead of chlorine and some people don't like it.

 

[seilsel]

Thanks chem_geek. You remain the man.