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Thread: Salt loss when having to use liquid chlorine for 2 weeks?

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    Salt loss when having to use liquid chlorine for 2 weeks?

    I posted before that my SWG cell went out around two weeks ago. During that time I used bleach to maintain my chlorine levels. My pool guy (just used for supplies and repair issues) brought a functioning cell (two days ago) to use in place of my broken one until the new one comes in. After turning on the SWG, the level read 1500. Just a week before, before the old cell went bad, the level was 2900. Would a two week span of this cause my salt levels to drop that low under normal operating conditions? We had about 4 inches of rain one day and I had to drain water out to get below the top of the skimmer, but this didn't affect my other numbers, so I wouldn't think that the salt would be affected that much either.

    I have added 3 bags of salt and now my reading is 2100. According to my calculations, I should be closer to 2500. (I added the salt, left the SWG off for 24 hours, then turned it on and it's been on for about 14 hours)

    Is this loss normal when adding bleach to the pool for CH maintenance? I have only otherwise had to add one bag of salt since startup in April (other than the large startup dose).
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
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    JasonLion's Avatar
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    No that is not normal. The salt level won't have gone down more than perhaps 200 or 300. Anything that would lower salt as much as you describe will have also lowered your CYA level very dramatically and affected the other levels in large but less predictable ways.

    When a cell is nearing the end of it's life the salt reading on the SWG can read lower than actual. Perhaps the cell he lent you is used and near the end of it's life?
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    I don't know anything about the temporary cell, I wasn't here when he did the work. I guess my next question would be, if I get the level up to where this cell will generate and it is actually too high, will that be an issue when I get the new cell?
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    I put far more trust in manually testing the salt level than relying on the SWG controller. The one on my sisters pool often reads FAR off from what the actual salt level really is. Adding more salt to the pool is easy, but the only way to remove it if you go too high is to drain off some of the water. I'd leave it alone until you know the true salt content and the new cell is installed.
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    Well, I wish I had posted this before the first 3 bags of salt I added due to the low reading. The level with the new cell is reading 3900 after first installing. Salinity was reading - 5400. So, now I'm draining water from the pool to add fresh. Yah....
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
    Pool School, Pool Calculator

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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    I know after my drain/refill, I'm going to have to adjust some numbers. What numbers will be changed the most? Obviously CYA and FC will be down, but what about pH and TA? CH?
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
    Pool School, Pool Calculator

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    JasonLion's Avatar
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    PH, TA, and CH levels will depend on the PH, TA, and CH levels of your fill water. Most of the time TA and CH will be lower in the fill water and so go down, but in some areas it can be the other way around.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    Already started refilling, should be ready by tomorrow for getting good test numbers. I guess I need to check my fill water at some point. I hadn't checked it yet because I haven't had to fill hardly at all thus far.
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    The saga continues. I set my alarm last night so I could get up and turn the water off. The volume was turned down too low, so it didn't wake me up. when I got up this morning, the water was 1/4 in. from the top of the pool. Awesome. I'm really loving my pool right now...
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
    Pool School, Pool Calculator

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    Re: Salt loss when having to use liquid chlorine for 2 weeks

    After the drain, fill, drain again saga, here are my numbers, before adding anything other than running the SWG.

    FC - 6.5
    CC - .5
    pH - 7.6
    T/A - 80
    CH - 160
    CYA - 25
    Salt - 4100 (I expect this to fall some more as it calibrates)

    I'm going to the store to pick up some CYA since I'm out of it at the moment, but I'm going to go ahead and add the calcium to get it up to 200 since I already have some on hand. Want to get it in spec for my heater anyway. I was worried that the numbers were going to be way off after the drain/refill, but they're really not all that bad. Not looking forward to the water bill though.
    15x32 vinyl liner, 14,400 gal, 1.4hp Centurion pump, 3/4 hp booster pump, Hayward Pro Series S244T Sand Filter, Hayward H200 heater (digital readout)
    Aqua Rite Electronic Chlorine Generator, Hayward Phantom cleaner, TF 100 test kit
    Pool School, Pool Calculator

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