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Thread: Disadvantages of SWG

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    Disadvantages of SWG

    This side conversation was split off of this topic.

    Mario P, I was in your shoes last year, so here is what I found in research, over my first year, and what my PB told me about SWG.

    SWG is not maintenance free. You will end up having to add muriatic acid to your pool to fight the PH in the pool. SWG turns your pool basic, so the acid brings it back neutral. Not a big deal, but just a different type of maintenance.

    The SWG has a cell in it that will need to be replaced, and they are not super cheap. Cell might last 1 year, might last 3, might last 5 or more. But it is a cost that definitely will need to be spent at some point in your future.

    The salt in your pool will cause more corrosion to things that if it were not there. People are correct that it is 1/10 ocean water, but that doesn't mean it is not salty. If you have a lot of plants around the pool, the salt an be a bit of an issue as your kids drip and splash around the pool. Of course, plants hate chlorine as well, so salt or not, this is an issue.

    I ultimately went without SWG. I just add bleach to the pool to keep chrlorine up, and when I am going to be away for travel, I will throw a couple of pucks into the Rainbow unit to keep it good when I cant maintain it. It has been my opinion here that people give you the opinion that one chlorine puck will ruin your pool. While their heart is in the right place, and the fact that pucks equal higher CYA, and higher CYA equals problems, an occasional puck wont kill your pool. All you have to do is keep an eye on your CYA via testing, and dont let it get out of control. Now if you only use pucks, CYA will get out of control and cause you problems.
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    JasonLion's Avatar
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    Re: Why is PB so against the SWG?

    Yev, there are a number of incorrect statements in your post, though it is certainly true that some people exaggerate the advantages of a SWG.

    Quote Originally Posted by Yev View Post
    You will end up having to add muriatic acid to your pool to fight the PH in the pool. SWG turns your pool basic, so the acid brings it back neutral.
    The SWG is net PH neutral. PH usually raises because TA is too high and the SWG provides aeration. Most pools can have the TA adjusted so the PH is stable. I have a SWG and haven't added acid in three years.

    The long term costs of a SWG, including replacing the cell, are roughly the same as buying chlorine. In some cases more, in some cases less.

    Plants really don't care about chlorine at pool concentrations at all.

    Salt can be a problem for plants in arid climates, but is only an issue for the most sensitive plants in more moderate climates.

    Only certain materials will corrode due to salt. Most common pool materials are effectively immune to corrosion from SWG levels of salt. SWG levels of salt will have no detectable effect on pumps, heaters, plaster, vinyl, PVC pipes, most ladders, etc.
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    Re: Why is PB so against the SWG?

    Quote Originally Posted by JasonLion View Post
    Salt can be a problem for plants in arid climates, but is only an issue for the most sensitive plants in more moderate climates.

    Only certain materials will corrode due to salt. Most common pool materials are effectively immune to corrosion from SWG levels of salt. SWG levels of salt will have no detectable effect on pumps, heaters, plaster, vinyl, PVC pipes, most ladders, etc.
    JasonLion, there is an incorrect statement in your attempt to correct me. But first I will say thanks for the TA/Acid correction. I was actually not clear about that, and from reading the forum, so many peoples threads talk about having to add acid to the pool with SWG. I guess I misunderstood that the TA problem could be better addressed to prevent the need for acid. I still have lots to learn about pools.

    As far as salt goes, salt is terrible for plants in any climate. Ocean water has a salt concentration of about 600 milimoles (mM). Concentrations as low as 40-50 mM will start to damage plants. This is half the salt concentration as water from a SWG pool. And it should be noted that I use the word damaged. At low levels, salt will begin to dehydrate the plant. This creates less foliage, slower growth rate, etc. The higher the salt level, the more dehydration, and thus more likelihood of death. People need to remember that salt was one of the first chemical weapons ever used by ancient armies who would put salt in their enemies crop fields to destroy the harvest and starve their enemies.

    But more related to the original topic. I was not referring to salt corroding anything directly related to the pool. I was referring to things more like any type of non-stainless screw or nail around the pool, such as a screw holding a table or chair together. Or any rebar in poured concrete where they may be a crack in an expansion joint.
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    Re: Why is PB so against the SWG?

    Many many people water their lawn with water from a SWG pool when backwashing with no problems what so ever. The portion of the lawn watered with pool water usually does way better than the portion that does not receive pool water.

    In the plant world, levels of salt up to 2,000 ppm are considered non-saline, while levels between 2,000 and 4,000 are considered only weakly saline. The vast majority of plants are just fine with weakly saline water.

    Different plants have different sensitivity levels, so there certainly are plants that will have problems, but most common yard plants are fine with SWG levels of salt in moderate climates. In arid climates the salt can build up in the soil and becomes far more dangerous.

    Salt levels for "chemical weapons" are dramatically higher than what is used in a SWG pool.
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    Re: Disadvantages of SWG

    Jason,

    I am very curious about the TA levels being too high and not having to add acid. I have to add acid on a weekly basis and follow strictly what is listed for SWG levels http://www.troublefreepool.com/conte...rine-generator Please enlighten what your TA level is that doesn't necessitate adding acid.

    Thank you.
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    Re: Disadvantages of SWG

    "High" TA plus aeration with result in CO2 outgassing, which raises the PH. There are two ways to minimize this. One is to lower TA, and the other is to raise PH. We only want to "raise" PH to a maximum of 7.8, so the goal is to lower TA until the PH will stabilize at 7.8. In normal conditions you don't want to lower TA below about 60. Fortunately, many pools will be stable with TA around 60. If that doesn't do it, then you can add borates, which allows you to lower TA as low as 40, which will certainly do it.
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    Re: Disadvantages of SWG

    Also, keep in mind that long-term use of bleach actually allows salt concentration to build up in non-SWG pools. While the concentration probably won't reach SWG-type levels, there are many scenarios where you can get about half of what you'll find in a SWG pool.
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    Re: Disadvantages of SWG

    Quote Originally Posted by otter86753 View Post
    Jason,

    I am very curious about the TA levels being too high and not having to add acid. I have to add acid on a weekly basis and follow strictly what is listed for SWG levels http://www.troublefreepool.com/conte...rine-generator Please enlighten what your TA level is that doesn't necessitate adding acid.

    Thank you.
    I am with you on the acid being a regular maintenance item. Even after three years since construction. And now that pool season is closer it will be even more cuz the bosslady likes to have the waterfall on. I just printed Jason's reply to your question and I'm going to get to work on my TA. It was 110 late last summer and down to 80 a couple of weeks ago. So, I'm going to drop it to 60 over the next couple of weeks and see if I can break my muriatic acid habit.
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    Re: Disadvantages of SWG

    Borates will allow you to drop TA to 40? Just let it drift down from the 70-80 when adding borates, and let it drift to a point where your PH stabilizes?
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    Re: Disadvantages of SWG

    arin, that is correct. It may take a while to get to the point where it is finally stable, but it will get there eventually. If you are impatient you can lower TA more aggressively.
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    Re: Disadvantages of SWG

    My pH is also rock solid. I didnt happen on purpose, I guess somehow I got lucky. But I havent added any MA in my SW pool since July last year.
    Im a solid 7.3 to 7.5 no matter what... TA is 60. No borates. So, at least for me, there is no disadvantage by the SWG causing pH to rise more quickly than a non swg pool.
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    Re: Disadvantages of SWG

    I just installed a SWG in my pool. The pool cover is still on as the weather here is still too cold for start-up. The more I read on the SWG, the more I hope I made the right decision to switch over from chlorine, LOL. I mean nails rusting in wood ?? Plants dying, Patio furniture rusting etc.... Are the naysayers environmentalists or what ???
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