Using Dichlor To Shock Bromine - Should I Test For Chlorine Too?

[PaulaME]

I'll be draining and refilling my spa on Friday. I've decided to stay with bromine. If I use shock that has Dichlor in it do I test for Chlorine levels also? If I use bromine (such as Brilliance pellets) that does not have any dichlor in it and use MPS to shock after each use - what happens if the spa isn't used for a few days? Without any dichlor in the pellets is there any sanitizing going on without daily shocking?

[chem geek]

Chlorine and bromine cannot be distinguished with standard pool/spa test kits. Their units of measurement are different where bromine is 2.25 times higher than chlorine -- most test kits that show both simplify this by showing bromine as 2x chlorine. So you don't and can't measure chlorine separate from bromine and don't need to.

If you use bromine tabs, that adds bromine to the water so if you aren't using the spa then it should maintain the bromine level. If the bromine level goes up, then you have the feeder open too wide. Bromine is a sanitizer so you don't need any daily shocking. That's the main advantage of using bromine tabs in a bromine system -- it maintains a background level of disinfectant without your having to add it yourself every day or two.