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Bromine To Salt Water Conversion


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I have a bromine pool, it has been a bromine pool for about 11 years. I am looking for information about converting it to a salt water chlorine-generating system. My goal in switching from bromine is to get more hours of open pool time. Currently our pool is covered all the time except when we are actually swimming. With the cover open I loose >2ppm/hour. The sun is very strong here in the desert at 6000 feet in elevation. As you can see after just 2 hours, I am below recommended sanitation levels. I am constantly fighting Br levels when the pool is open for any length of time. I have talked to my local pool care store and they tell me that all I have to do is wait for my free Br level to be zero, and just switch over to salt.

Won't the Cl generated in the salt water system just regenerate the Br from the Br bank in the pool? The pool care people say I don't need to drain my water. If I don't change the water, then won't I be measuring free Br and not free Cl with a generator? Will the generator react differently because there is Br in the water as it passes through the plates?

The cyuranic acid that is added as a stabilizer for Cl does not work for Br, will it cause any interferance or problems?

Why is the recommended level of CYA higher for salt water systems than fresh water systems? Doesn't a higher CYA conc require a higher free Cl level for sanitation? I would prefer to keep both CYA and free Cl levels as low as possible since both are carcinogens.

The guys at the pool store are clearly not water chemists, even though they have done this type of work for many years and they may be right, that I can just switch. Is there a publication or web site where I can get more technical/chemical information?

Are there other sanitation options available without draining the pool? 20,000 gallons is alot of water, and we are having a drought - with water use restrictions.

Thanks for your help!! Confused...need answers!! :blink:

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I have a bromine pool, it has been a bromine pool for about 11 years. I am looking for information about converting it to a salt water chlorine-generating system. My goal in switching from bromine is to get more hours of open pool time. Currently our pool is covered all the time except when we are actually swimming. With the cover open I loose >2ppm/hour. The sun is very strong here in the desert at 6000 feet in elevation. As you can see after just 2 hours, I am below recommended sanitation levels. I am constantly fighting Br levels when the pool is open for any length of time. I have talked to my local pool care store and they tell me that all I have to do is wait for my free Br level to be zero, and just switch over to salt.

If you have only used sodium bromide to create a bromine bank in the water and activated it with either chlorine or MPS then chlorine and sunlight will burn the bromine off in a few weeks. If you have used organic bromine tabs with DMH (dimethy hydantion) (the ingredient is BCDMH or bromo-chloro-dimethyl hydantoin) then you will have to drain and refill because this seems to make the bromine hang around forever.

Won't the Cl generated in the salt water system just regenerate the Br from the Br bank in the pool?

Yes, and you need to check with the manufacturer of the SWG to see if it can be used with bromine, some can and some cannot.

The pool care people say I don't need to drain my water. If I don't change the water, then won't I be measuring free Br and not free Cl with a generator?

If you test for chlorine and the level tests ok then if it is bromine the level will be fine also since bromine needs to be run about twice as high as chlorine and a chlorine test in a bromine pool multiplied by 2.25 will give you the bromine level.

Will the generator react differently because there is Br in the water as it passes through the plates?

Depends on the SWG...see above

The cyuranic acid that is added as a stabilizer for Cl does not work for Br, will it cause any interferance or problems?

This I don't know. I don't believe so.

Why is the recommended level of CYA higher for salt water systems than fresh water systems? Doesn't a higher CYA conc require a higher free Cl level for sanitation? I would prefer to keep both CYA and free Cl levels as low as possible since both are carcinogens.

First let me say HOGWASH to the carcinogen scare! Not the time or place to get into it though.

The reason that the higher CYA level is needed as was explained to me by both tech support at Goldline Controls and Autopilot System is because the way the chlorine is introduces at such high concentrations in the cell in a continuous basis while the cell is generating. I peronally run my CYA at 70-80 ppm and my FC at 2-3 ppm in my pool and 3-4 ppm in my spa with an Aqualogic PS-8 system. You are right about high CYA levels needing higher FC levels in a manually chorinated pool, however.

The guys at the pool store are clearly not water chemists, even though they have done this type of work for many years and they may be right, that I can just switch. Is there a publication or web site where I can get more technical/chemical information?

Send me a PM.

Are there other sanitation options available without draining the pool? 20,000 gallons is alot of water, and we are having a drought - with water use restrictions.

IMHO, if your SWG is bromine capable just run it as a chlorine pool, test for chlorine, and run the cell output high enough to maintain the proper FC level and after a while try adding CYA(maybe about 40-50 ppm) to see if you can turn the output down. If the pool is still bromine the CYA won't make any difference but if the bromine is gone then you finally have a chlorine pool and you can bump up the CYA level to manufacturer's recommendations (this varies from manufacturer to manufacturer...Some recommend as low as 50 ppm, the majority seem to be 60-80 ppm and I know of one (Poolex) that recommends 80-100 with salt levels of 4500-5500 ppm)

Thanks for your help!! Confused...need answers!! :blink:

Hope this is helpful! As an alternative, you might want to consider staying with bromine and adding an ozone generator. Ozone is very effective at reactivating the bromine bank and is best used in a bromine pool. The constant regeneration of the bromine bank might help maintain a more even sanitizer level in your pool. In a chlorine pool ozone just kills the chlorine and chlorine kills the ozone so they fight against each other!

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