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Thread: SWG - bromine vs chlorine

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    SWG - bromine vs chlorine

    I have just received a used ( but in great condition) Hot Springs Sovereign hot tub. I've maintained a pool before, but not a hot tub. I'm trying to decide about water treatment.

    I'm confused about the two types of SWGs. I've researched both, but found few options for Bromine SWGs. I've also read that Sodium Bromide is expensive for water change outs.

    Everything I've read regarding Spas w/o SWG systems suggest Bromine is the way to go because of hot tub temperatures. But with SWGs for Spas, most of what's available are chlorine generators.

    What am I missing?
    Does anyone have some lasting success with a particular reasonably priced SWG of either type?

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    JoyfulNoise's Avatar
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    Re: SWG - bromine vs chlorine

    The is no such thing as a salt water bromine generator. The closest thing would be to use sodium bromide in the tub and establish a bromide bank. Then you would use an SWG to create chlorine which would then activate the bromide into bromine. But that's a very convoluted method.

    Many members simply follow the dichlor-then-bleach method outlined in this sticky - How do I use Chlorine in my Spa (or pool)?)

    It's a lot easier and cheaper than bromine. The only down side is daily chlorine (bleach) additions. If that's an issue, they do sell drape-over mini SWGs for generating chlorine in a hot tub and many members use them along with the process described above.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: SWG - bromine vs chlorine

    If you have plain salted water then your sanitizer will be the chlorine generated by the swg. If you add bromide to your salted water then the chlorine generated by the swg will be instantly converted to bromine (which is said to work better in warm water than chlorine).

    A bromide pack to establish a "bank" (@ 30ppm) in your water will cost less than $4.00 at your local big box store and lasts until you change the water.
    The bromide is not "used up" when it is converted to bromine. After it does it's job it reverts back to bromide.

    You can introduce chlorine manually (adding bleach) to convert the bromide to bromine or a swg can continuously create chlorine for you at a rate of your chosing rather than you having to manually add chlorine every day (or as needed).

    An "in between" method of maintaining a proper level of sanitizer is to have a floater with bromine tablets in it. It continuously leaches chlorine and bromide (which you don't really need because you have already added enough via the starter pack) into you water.
    This method is tougher to find the "sweet spot" for the correct level of sanitation vs a swg but it's less effort than adding chlorine manually. It also costs a bit more than bleach and you'll still need to add some bleach after bathing to account for the extra load on the sanitizer.
    A swg is more controllable/predictable and most of them have a "boost" setting that you would use after bathing instead of having to add extra bleach.
    Hot Springs Sovereign (1999?)

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    Isaac-1's Avatar
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    Re: SWG - bromine vs chlorine

    As you can see it can be a complex issue, personally I opted to use a drop in SWG (Saltron Mini), When I refill my tub I start off initially filling with pool water as it is already balanced and has CYA in it, then just add salt (about 7 pounds in my case with a small hot tub) and let the SWG do its thing. If I did not have a pool I would fill, add salt then add dichlor for the first few days until CYA built up then switch to the the SWG.

    I have been using this method since I bought my used Hot Spring Jetsetter almost 3 years ago, there are some concerns with salt water in a hot tub and shortening equipment life. So far in 3 years I have went through 2 circulation pumps at about $180 each, I don't know if this is salt related or just bad luck. My tub is a 1998 Hot Spring Jetsetter which I bought from a guy that had it in storage for several years after he acquired it from the original owner who had it installed indoors, so it overall was in good condition for its age when I bought it. I did initially have to replace some leaking diverter seals, install a new ozonator, new circulation pump, replaced a couple of spinner jets which had bad bearing, replaced the cracking pillow, etc. However since the initial refurbishment I have done no other mechanical work to the tub other than the 2 circulation pumps mentioned above.

    Ike

    p.s. I am still on the original SWG cell
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    Re: SWG - bromine vs chlorine

    Quote Originally Posted by Isaac-1 View Post
    I opted to use a drop in SWG (Saltron Mini), When I refill my tub I start off initially filling with pool water as it is already balanced and has CYA in it, then just add salt (about 7 pounds in my case with a small hot tub) and let the SWG do its thing. If I did not have a pool I would fill, add salt then add dichlor for the first few days until CYA built up then switch to the the SWG.
    Just so the OP understands...he is using chlorine as his sanitizer, as opposed to bromine. Bromine doesn't need CYA.
    Either one is effective. It's personal preference which to use. Try both and decide which works best for you.
    Hot Springs Sovereign (1999?)

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    JoyfulNoise's Avatar
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    SWG - bromine vs chlorine

    One thing to warn about us the of bromine tablets (BCDMH). Like stabilized chlorine in pools that eventually adds too much CYA, bromine tabs will eventually add too much dimethylhydantoin (DMH) that, like CYA in swimming pools, will over stabilize the hot tub water and reduce bromine's effectiveness. Bromine tabs tend to dissolve rapidly in hot spas and so they will add too much bromine and DMH over time. There is no way to test independently for DMH so the only thing you can do is keep good records of addition and dump the hot tub when the DMH is too high.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: SWG - bromine vs chlorine

    Good point. I'd like to get away from the tabs and just use bromide + a SWCG.
    I just don't have the extra $ due to a daughter in college.
    Hot Springs Sovereign (1999?)

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