Bromine chemistry

[giulietta1]

I have had some indications that bromine is the sanitizer of choice for hot water applications. I am buying a used hot tub (fiberglass) and am thinking I'll prolly use bromine. I've learned a little about it, but I still have Q's.

When filling, apparently one must use some sort of start-up (like "Go Brom") to activate the bromine. . it's slow-dissolving or something? I'm not entirely clear on the whys and wherefores of that.

What about cleaners? There seem to be a wide array of them, and the marketing materials indicate one needs more than one. There's spa cleaner, and spa gloss. . . suggestions? Does one really need specialized cleaners or is that just hype?

 

[crazycanuck]

OK I am new to hot tubs too, but from what I understand is that Bromine stands up to heat better than chlorine, but it doesnt mean you can't use chlorine, it just means you have to keep a closer eye on the chlorine as it breaks down faster under those conditions. And if you do use Chlorine, I believe you are suppose to use the Unstabilized Chlorine, don't ask me why.

I use the bromine system. what happens on first fill is that if you use those floating bromine tablets like myself, you have to establish a bromine reserve... that little floaty thing isnt going to provide enough bromine on startup to keep up with the sanitary demands of your hot tub, I use the 2 part bromine system on startup, part a is liquid bromine and part b is the activant which activates the bromine, which I believe is an oxidizer. Its probably the same as what you are referring to which is "go brom"

From then on I just use the bromine tabs. I think for a hottub you're looking at about 6ppm for bromine. As for those cleaners, and things that decrease the suds etc, I have them too, I use them occasionally cause it makes me feel good I guess, does it work, not sure.

Hope that helps!

 

[giulietta1]

Thank you, I appreciate your input! Yes, I think the rule is 2-6 ppm of sanitizer for spas. I'm interested in using bromine for the spa b/c I had read that bromine is more suitable for hot water chemistry than chlorine.

I suspect that unstabilized chlorine is recommended for spas b/c they're often either indoors or covered. Without the sun shining on the water, the spa water wouldn't get enough UV to break down the chlorine.

What about the spa cleaners and such? Do you use anything special, or just ordinary household cleaners, like 409 or some such? (Or maybe you haven't had the spa long enough to need them??)

I'm not sure why special cleaners would be necessary, unless it was to minimize residue which could contaminate the water.

Also, I use Pool Perfect in my pool; it's an enzymatic product that assists in the breakdown of organic wastes and helps prevent chloramine accumulation. It's supposed to prevent the waterline ring and scum buildup. There's also a Spa Perfect, but it sounds to me like that is just a diluted version of the Pool Perfect! Seems like it would make more (economic) sense to use a teaspoon of Pool Perfect in the spa instead of 3-4 oz of Spa Perfect. . .

Anyone else feel free to chime in here!

 

[Guest]

Here is a primer on bromine chemistry in a ACRYLIC portable spa:
1) On each fill add enough sodium bromide to provide a 'bromine reserve' in the water. You then shock the hot tub with either unstabilized chlorine or MPS (non chlorine shock). I prefer liquid chlorine or laundry bleach for shocking. This will oxidize the sodium bromide to hypobromous acid (your active sanitizer that you are testing for). One cup of regular strength bleach or 3/4 cup of ultra strength bleach is about the right amount for a 300 gal spa. This should bring your bromine levels slightly above 10 ppm. Wait for the level to drop to between 4-6 ppm
2) put in your floater with bromine tablets and adjust it to maintain the 4-6 ppm bromine level. (this step is optional)
3) oxidize (shock) once every week or two or when your bromine levels drop too low. Wait for the bromine to drop below 10 ppm before entering the tub.
4) Drain and refill every 3-4 months and start over.

Be sure an balance the water before adding the sodium bromide. First adjust TA to around 100 ppm, then adjust pH to about 7.6, then if you hardness is low adjust the calcium to at least 125 ppm. Be sure and have your fill water tested for metals and if present add a metal sequsterant.

If you are using Ozone be aware that it will always be oxidizing the sodium bromide and you might find that your floater will need to be ajusted down accordinly. Also be aware that ozone will form bromates in your water faster (these are considered unhealthy) and you should probably drain and refill more often.

Bromine is considered more stable at high temps and also the bromamines that form are considered to be effective sanitizers. However, bromine is a known sensitizer and many people do develop an allergic reaction to it. It also has a decided chemical smell. IMHO, it's main benefit would be in an indoor hot tub but the jury is still out on that.

As far as PoolPerfect vs. SpaPerfect--I contacted NaturalChemisty a while back about the differences and they told me that SpaPerfect is formulated to deal with the higher organic load found in a spa vs. a pool. Enzymes are useful but expensive additions but they do work. You might want to invest in a 'scumbug' or 'sunsorb' and let it float in your tub. This is a sponge made of a special plastic that will adsorb oily deposits from the water surface and will greatly reduce a scum line from forming. When the sponge gets dirty just turn it over and when that side is dirty just rinse it out. They last several seasons and only cost about $6-$7 bucks.

As far as bromine vs. chlorine--I have found from my experience that bromine does not require the daily maintenance that chlorine does and is a bit more forgiving if you ignore the spa for a week or two. I still would choose chlorine over bromine in a portable spa (and have used both in the past when I had portable spas.)

The reason that many state health departments now recommend using unstabilzed chlorine in spas is because the cyanuic acid found in dichlor (stabilized chlorine used in spas) quickly builds up to levels that inactivate the sanitizing ability of chlorine, leading to 'hot tub itch (pseudomonas). However, if there is NO cyanuric acid in the water and the spa is exposed to sunlight then the chlorine will 'burn off' in a very short time. It might be advantageous to bring the CYA level to about 20 ppm if you are using chlorine and at that point use only unstabilized chlorine in the spa.

Bromine is not immune to this stabilizing effect. The dimethylhydantion used in the bromine tabs has a similar effect on bromine, which is why periodic drains and refills are necessary.

 

[crazycanuck]

hey waterbear, can you expand more on bromates? my hot tub has an ozonator.

 

[giulietta1]

Thanks, Waterbear! That really clears things up for me. I've printed it out to keep for reference.

 

[Guest]

hey waterbear, can you expand more on bromates? my hot tub has an ozonator.

bromates are a suspected carcinogen--the operative word here is suspected!

 

[crazycanuck]

WOW!

 

[giulietta1]

My bromine has been going really high! (like 10-12) Does shocking with MPS do that? It reactivates those combined bromines, I understand. . . I had added more bromine tabs to my dispenser too.

I tested for the MPS before doing the bromine test; there was very little residual MPS so it wasn't that interfering with the test.

I have ordered the FAS-DPD bromine reagent, but until I receive that I'm stuck with the guesstimates from the cheap test. Those do indicate it's on the high side. I took out the dispenser and left the cover open for a couple of hours during the afternoon and that helped lower the bromine.

Any ideas on what may have caused these elevated levels? The shocking, the added bromine tabs, or some other factor? The pH has been at a good level, around 7.3-7.5.

 

[Guest]

My bromine has been going really high! (like 10-12) Does shocking with MPS do that? It reactivates those combined bromines, I understand. . . I had added more bromine tabs to my dispenser too.
Yes, it oxidized the bromide reserve in your water back into hypobromous acid (bromine sanitizer). That is what it is supposed to do
I tested for the MPS before doing the bromine test; there was very little residual MPS so it wasn't that interfering with the test.
How did you test for MPS? The test strips that are out to test for them are the same test as for total chlorine or total bromine. There really isn't a test just for MPS. There are reagents available to remove the interference it causes to the combined chlorine test.
I have ordered the FAS-DPD bromine reagent, but until I receive that I'm stuck with the guesstimates from the cheap test. Those do indicate it's on the high side. I took out the dispenser and left the cover open for a couple of hours during the afternoon and that helped lower the bromine.
That would be the proper procedure. When you shock you are purposely raising your bromine levels to burn off organics in the water and to reactivate the bromide reserves into bromine sanitizer. You then need to let the bromine level drop to normal range. Your floater is just used to help maintain the bromine level on a day to day basis.
Any ideas on what may have caused these elevated levels? The shocking, the added bromine tabs, or some other factor? The pH has been at a good level, around 7.3-7.5.

Hope this explains what happened.

 

[giulietta1]

Thanks, Evan. That makes sense. Guess I need to take the duck (dispenser) out of the spa for a while!

I'm using the Aquachek strips to test for MPS. . . I take a water sample and then add thiosulfate, swirl and then dip the strip. Is the thiosulfate neutralizing the MPS too? I have ordered the deox reagent, BTW. Just haven't rec'd it yet.

Thx,
Jules