Shocking a Bromine pool - can I use chlorine shock

[chem geek]

Yes, you can use chlorine to shock or reactivate bromide to bromine in a bromine pool. You do not have to use more expensive non-chlorine shock for this purpose. The chlorine will convert to chloride salt when it reactivates bromide to bromine so you end up with bromine, not chlorine.

As for how to convert a bromine pool to a chlorine pool, Ben described the situation as "once a bromine pool, always a bromine pool" and talks about this in more detail at PoolSolutions. If you didn't use bromine tabs, but used sodium bromide with shocking using chlorine or non-chlorine shock to activate the bromine, then IF there isn't too much bromide and bromine in the water then it can slowly outgas over time (months, usually) and eventually become a chlorine pool again.

The problem is that there is no readily available consumer test kit for either bromide or bromine as distinct from chloride or chlorine. Bromine test kits don't distinguish chlorine from bromine which is why there are test kits that show both scales since they are measuring the same thing, only in different units (bromine units are 2.25 times higher than chlorine, though most test kits only show this as 2 times higher). So the only way you have any clue as to what you have is from the daily usage which in sunlight may be somewhat higher when using bromine. Perhaps the smell is somewhat different as well, though that can be hard to detect.

For all of these reasons, one is usually told that if you want to convert a bromine pool back to chlorine, you have to do a complete water replacement.

Richard