Can't get bromine levels up!

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boisepoolnerd

0
Oct 3, 2016
10
Meridian, Idaho
Hi all,

First post, but I've been a long time lurker. I have a 18000 gallon plaster pool that we built in 2013 and I've been using the BBB method since day 1 to maintain it with absolutely zero issues. I've learned a lot here and I've very grateful.

Last week we received a new spa. Based on all of the research I did I decided to go with bromine. I started it up but I couldn't get the bromine levels to stay above 0. Did more reading here....ran a bottle of Leisure Time Jet Clean per the instructions on the bottle. I'd seen some nasty looking pictures on the web, so I was a little disappointed that I just made nice white foam. Regardless, I drained, rinsed, and refilled.

I'm having the same issue still. The spa has been left unoccupied all day, and here's what I came home to:

pH 7.6
bromine <1.25 ppm (using the FAS-DPD test, solution was pink but went clear with a single drop of titrant)
CH 200
TA 40
I should have 30 ppm bromide bank (added 60g of NaBr at fill, tub is 380 gallons)
Haven't added boric acid to this fill yet

After the fill I added bleach (160 mL of 8.25%) to shock (~48 hours ago).

Tub has an ozonator, and I've got a single tablet floater that's cranked wide open with 5 bromine tablets in it. Any ideas as to why I'm not maintaining a significantly higher Br concentration?

Thanks in advance!
Boisepoolnerd
 
Add a couple of ounces of bleach and then test for bromine and combined oxidizer after 10 minutes.

Most bromine testing says that the combined portion of the test is not needed since bromamines register in the first part of the test. However, I have found that a bromine tub often has significant levels of combined oxidizer.

Note: I’m not really sure what is reacting with the iodide in the combined portion of the test.
 
Thanks for the suggestion James, but I don't really understand what this would do. If I add bleach then I should see the oxidizer (bromine) jump. What am I missing?

Turns out after I saw your post everything seemed to be fine. Bromine was up around 5 ppm. I was leaving for a long weekend so I shocked with bleach and when I returned home I still had high bromine levels (>15 ppm). I closed down my floater (it had been pretty much wide open). After the Br went below 10 ppm we started using the tub again and now I'm back where I started....I have detectable Br but the FAS-DPD test goes clear with a single drop (<1.25 ppm). I've started to open the floater back up but I can't seem to get the Br up.

I'm getting pretty frustrated at this point....I have no issues with my pool.....and I'm an industrial analytical chemist. Any ideas/suggestions/help is greatly appreciated!

bpn
 
You might be getting combined oxidizer that needs reagent R-0003 to be seen.

R-0003 is iodide, which is easily oxidized to iodine by many oxidizers. The iodine then shows up in the test.

Theoretically, combined bromine (bromamines) should not need iodide to show up whereas combined chlorine (such as chloramines) does. However, I have found that the bromine either combines with something or oxidizes something that needs iodide to test.

Do you have an ozonator?
 
James,

I added 200 mL of 8.25% bleach to my tub (380 gallons) and waited 10 minutes.

With a 10 mL water sample I used 16 drops of titrant (20 ppm free Br?) then added the R0003 reagent. It took 4 drops of titrant to go clear (5 ppm combined bromine?)

So what should I take away from this experiment?

edit: just saw your question - yes I have an ozonator.

Thanks,
bpn
 
Total Bromine Test
1. Rinse and fill large comparator tube to desired mark with water to be tested.
NOTE: For 1 drop = 0.5 ppm, use 25 mL sample.
For 1 drop = 1.25 ppm, use 10 mL sample.
2. Add 2 dippers R-0870. Swirl until dissolved. If total bromine is present, sample will turn pink.
NOTE: If pink color disappears, add R-0870 until color turns pink.
3. Add R-0872 dropwise, swirling and counting after each drop, until color changes from pink to
colorless.
4. Multiply drops in Step 3 by drop equivalence (Step 1). Record as parts per million (ppm) total bromine.
Click to expand...

Is this the test you're doing?
 
Ok, so you’re getting about 25 ppm total. That’s close enough to the 27 ppm expected.

Most likely, the bromine is just getting used up. Hot tubs have a high demand from contaminants.

Check in an hour or two to see if the bromine disappears quickly.

Maybe try turning the ozonator off to see what effect that has.
 

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If this is a brand new hot tub, it shouldn't have this much sanitizer demand.

If it's a used tub, it might have biofilms growing in the equipment or a fouled filter.

Not sure what else to check.
 
Thanks for your help. Brand new tub. I filled the first time and it behaved like this. I ran jet cleaner and refilled. Same issues.


On the first fill the water looked brown/nasty but it cleared up pretty well after the water was balanced and filtered. Tub had been wet tested by the manufacturer and had water in it when I received it. Did I miss something at startup that I should have done?

This thing is driving me crazy. It's way too much work and almost no upside. If I had a cliff I'd be tempted to push it off.
 
After running overnight (the pump would have came on for a 30 minute filter cycle, and I assume things ran for heat as well). Free bromine = 15 ppm, combined = 1.25. So it dropped by ~1 ppm in the last 9 hours (ozonator would have run with the filter cycle and I had the tab floater in there).
 
If the spa was had gunk in it at startup, that gunk may be causing your higher than expected bromine usage. Brand new spas can have gunk/slime/biofilms due to stagnate water sitting in the lines while the spa sat around after testing.

My bromine spa is only about 6 weeks old now and was brand new. At the 4 week mark we had an issue with the water going cloudy (wife forgot to add bleach after a lot of use one night). I used the SLAM method for about a day, then realized it would be cheaper just to drain and refill instead going through bleach and testing supplies. The best decision I made was to order some Ahh-Some to clean the spa before I drained it. Even on my almost brand new spa, I got a bit of nasty brown gunk out of the lines. Post refill my spa is clean and clear and uses much less sanitizer. I wish I had used Ahh-Some before I filled it the 1st time.

Summary: You new spa was probably funky when you got it. It will probably be easier and cheaper to just hit it with Ahh-Some, drain, refill, start over.
 
One thing to remember about bromine tablets is this - they are often a mixture of halogenated dimethylhydantoin's. Excessive DMH build up can be a problem just like too much CYA in a chlorine pool - the DMH can over-stabilized the bromine and thus lead to lower active bromine sanitizer (hypobromous acid) levels. So even if you measure a correct bromine level, too much DMH can make it less effective. This is why bromine tablets are good for sanitation of the spa when you can't test for a few days but constant, long term use is bad. You want a bromide bank in the water so that you can simply use chlorine (or your ozonator) to reactivate the bromine by converting bromide to bromine. Over use of BCDMH tablets is as bad as over use of trichlor or dichlor in a swimming pool.

Finally, while the ozonator can help support a bromine level in the water by converting bromide to bromine, many are not capable of putting out enough ozone to get for zero to full sanitizer levels. Again, like an SWG in a swimming pool, you need to establish the free chlorine level using bleach or liquid chlorine and then let the SWG maintain it for you.
 
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