Convert bromine to chlorine?

[wildlifer]

Just bought a house with an inground vinyl lined pool which the previous owner used bromine tabs in for several years. Can this be converted to chlorine at the beginning of the season without a complete draining of the pool?

[PoolDoc]

Where BCDMH tabs have been used for several years, there's going to be a high level of both DMH residue and bromide ions. Chlorine instantaneously converts bromide to bromine or bromate. Conversion to bromate is permanent (more or less) and prevents further bromine 'regeneration'. With pure bromide based 'bromine' pools, bromate formation when chlorine is added makes it possible to end the bromine cycle.

But the DMH apparently inhibits bromate formation, leading to an endless cycle of chlorine => bromide conversion => bromine consumption => conversion to bromide, and then repeat with more chlorine.

Regardless, so long as bromide ions remain in the pool, your pool will be a bromine pool, since any added chlorine will react with the bromide much faster than anything else in the pool. Repeated high levels of added chlorine might eventually convert the bromide to bromate, but I'm only guessing.

BTW, don't drain a liner pool at all, or a concrete pool if the ground water level is high! Doing either one will destroy the pool.

[wildlifer]

Thanks for the reply - the old adage "once a bromine pool always a bromine pool" holds to be true. I will continue with bromine and will consider changing only when the time comes to replace the liner.

[PoolDoc]

Wow!

I know I'm getting old, but I only wrote that "old adage" for the first time, about 14 years ago. That doesn't seem all THAT long ago.

Maybe, "middle-aged adage"?

[wildlifer]

Okay, I spoke to our local pool professionals today (they are also the installers of my pool) and they say it can be done as long as you weren't using a bromine feeder. In my case the bromine tabs were dissolved in an Aqua Genie dispenser. This dispenser must be thoroughly cleaned of all traces of bromine before being used for chlorine. The problem is that I won't get a chlorine reading for a long time, perhaps months, until all of the bromide is used up. The pool will be sanitized but I will have to rely on the appearance of the water to determine if I am feeding enough chlorine into the system. He says this is not too difficult and eventually I will begin to see chlorine readings as the residual bromide is used up. Anyone had any experience with this?

[PoolDoc]

They're wrong -- but you're the one who has to pick who you are going to trust.

Locking this thread; we've done the bromine debate before and there's no point in wasting time on doing it again during the Forum's saturation period of late May - early July.

Good luck!