Weird Problem With Bromine Levels

[shaner]

A week ago I drained my hot tub. I did the whole decontamination method. Cleaned out the pipes, drained, superchlorinated, drained, re-filled and did the 3 step bromine method. My water looked better than ever and my bromine levels were more stable than ever before.

Last night I had a bunch of people in my hot tub and this morning when I tested the water the bromine level was 0. I decided to really give it a good shocking so I added about 12 ounces of 6% bleach then left it covered. I tested it about 7 hours later hoping it would be under 10 so I could use it, and found the bromine level to be at 1.5. This really surprised me as I just dumped in a lot of bleach.

I just added another 8 ounces of bleach and I'm going to go test it in a couple hours, but I have a couple questions.

The bromine levels likely sat at 0 overnight after everyone got out. Does this mean I now have a little bug growing in my hot tub that is eating up all my bromine? If so, can I kill it by continuing to shock until the levels stabilize again? Or is it more likely there was just so much sweat/oils/urine etc. (I hope no urine, but you just never know when people are drinking) that the chlorine I dumped in initially had to kill all that which is why it got used up so quickly? The water was cloudy but seems to be mostly clear again. I don't have to drain and re-fill again do I?

I know the problems with leaving bromine levels at 0 for any period of time, but when you get out very late at night and you've been drinking, you don't always think responsibly.

[waterbear]

IF the water was cloudy then there was either a very large organic load or there was something growing.

Did you test the bromine level after you added the bleach? How did you test (FAS-DPD, DPD, or strips?)

When you tested 1.5 ppm bromine how did you test?

Both DPD and strips can bleach out and test low when the sanitizer levels are high.

If the bromine is really low and not a false low because of bleachout (use an OTO test to verify, it comes with the comparator with shades of yellow and is found in the inexpensive two way drop based chlorine/bromine and pH testers). If the bromine is really 1.5 the color will be very pale yellow. If the color is yellow, deep yellow, orange, reddish, or brown then your other test did bleach out. If you used FAS-DPD testing it does not bleach out and is usable up to about 50 ppm bromine so 1.5 ppm is either correct or testing error. If correct then just shock the tub again and let us know how high the bromine level is a few minutes after shocking. (I assume you did add sodium bromide on filling the tub since you stated you were doing 3 step bromine).

You do not need to drain and refill so relax. You just need to shock (and if the organic load was high you might need to shock more than once), LEAVE THE COVER OFF THE TUB AFTER SHOCKING (EAND, IF POSSIBLE, EXPOSE THE TUB TO SUNLIGHT) to allow volitile oxidation byproducts to leave the water and you should be able to maintain your bromine level once again.

[shaner]

Thanks, I did exactly as you said. I had to shock the tub 3 times and now the bromine levels seem to be stable again. One thing I haven't been doing is leaving the cover off after I shock. I will make sure to start doing that. The water was very cloudy but seems to be clear again.

[waterbear]

I had to shock the tub 3 times

High organic/bather load. If it happens again keep your bromine a ppm or two higher than you are now and see if that helps.

Bottom line, if the water is cloudy and yo cannot maintain sanitizer then you have somethng in the tub that is using up the sanitizer and yo need to keep adding more (shocking) until the santizer demand is met.