Need help understanding the "Bromine Pool Problem"

[mskirtland]

Would somebody please help me understand the "once a bromine pool, always a promine pool" witticism that I keep reading. Everybody seems so happy to repeat that phrase but I don't know what it actually means.
I have a 30k gallon chlorine pool. While on vacation my neighbor called to tell me it looked like a swamp. A local pool company came out to rescue me by adding 2lbs of Yellow Treat, shock, and chlorine tabs in the floater. The pool is beautiful now. Strange thing is that I haven't added chlorine for over a week and it is still sparkling blue.

• Is there some crisis looming on the horizon that I don't know about?
  Do I keep adding chlorine as I usually do?
  Will the pool behave differently? What should I expect?
  I want to add a swg but am affraid that the Yellow Treat will damage it. Is this a reasonable fear?
  Any other comments/suggestions would be appreciated

Thank you for your help,
-Mike Kirtland
Yorba Linda, CA

 

[JamesW]

Yellow Treat is 88.8 % sodium bromide. Two pounds in your 30,000 gallon pool would add 5.5 ppm bromide to the water. 5.5 ppm bromide can be converted to 11 ppm bromine by 4.9 ppm of chlorine. This means that the first 4.9 ppm of any chlorine you add will become up to 11 ppm bromine and any chlorine over 4.9 ppm will remain as chlorine.

Since bromine is not protected by cyanuric acid, you could experience an accelerated loss of chlorine as the bromine is destroyed by the sunlight and the chlorine is converted into more bromine.

This will continue to happen until the bromide levels are reduced. Bromide might dissipate over time, especially if no bromine tabs were used.

You should monitor your FC and CC levels carefully using an FAS-DPD test kit. If you can post a full set of test results, that would help.