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Thread: Rebalancing after conversion to SWG

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    Question Rebalancing after conversion to SWG

    Hi All,

    I've just converted converted the pool at my new home to salt. I've been shifting the chemistry to an SWG setup and the pool has just started fading from crystal clear to picking up a slight green tint and getting cloudy. I'm shocking it right now, but can't understand why this is happening given the pool chemistry. I've been measuring every day as part of the rebalance and the numbers are coming up consistent, so I don't think it's measurement error.

    FC: 4 - 6 depending on cloud cover
    CC: 0, not the slightest hint of pink any time I've tested this
    pH: 7.2 - 7.8, so far dialing this in has been the hardest part
    TA: 70
    CH: 450, the water's hard here, not much I can do to get it lower, didn't present problems when I was using bleach
    CYA: 70-75
    Salt: 2700
    Water Temp: ~85

    No complaints on the Nano display, so how's it managing to green up on me?

    Thanks,
    Rob
    15k gallon, IG plaster pebble surface, single speed filter pump, sand filter, Polaris 280 cleaner w/ PB40 booster, AutoPilot Nano+ w/ RC-28 cell.

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    needsajet's Avatar
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    Re: Rebalancing after conversion to SWG

    Nice to meet you via TFP

    There's no real way to know the exact reason for visible algae and cloudiness, but the key right now is to SLAM the pool.

    This is the TFP procedure for the SLAM: Pool School - SLAM - Shock Level And Maintain

    The procedure needs to be followed thoroughly, and after that, you'll have better luck getting the water stabilized.

    Are you using muriatic acid for your pH adjustments?
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    jeffchap's Avatar
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    Re: Rebalancing after conversion to SWG

    Algae is always the result of insufficient chlorine. Given enough chlorine, algae simply cannot survive.

    We always round up our CYA to the next 10, so if you are 70+, read that as 80. The bare minimum FC for that is 5.6. If you've dropped to 4, that's too low. SLAM to kill it then target FC at 8 and never let it fall below 6.
    25000 gallon free-form gunite
    Jandy Stealth pump/CL340 cartridge filter
    Pentair IC40 SWG
    Pentair MasterTemp 250HD heater
    Jandy AquaLink RS automation

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    needsajet's Avatar
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    Re: Rebalancing after conversion to SWG

    It appears that the OP was following TFPC recommended FC levels for their SWG pool and CYA at 80 ppm. The bare minimum is 4 ppm FC and the target is 6 ppm FC.

    A few things that may contribute to an algae outbreak include lack of brushing, dead spots with inadequate water circulation, or higher than normal incoming load of organic contamination. It's indeed very important that the pool never fall below the bare minimum FC level.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: Rebalancing after conversion to SWG

    Quote Originally Posted by jeffchap View Post
    Algae is always the result of insufficient chlorine. Given enough chlorine, algae simply cannot survive.

    We always round up our CYA to the next 10, so if you are 70+, read that as 80. The bare minimum FC for that is 5.6. If you've dropped to 4, that's too low. SLAM to kill it then target FC at 8 and never let it fall below 6.
    I hear ya, but for what it's worth, the pool calculator says for SWG to target an FC level of 3 at 70 and 4 at 80. I understood those values to be the floor and haven't let it dip through them. Are you sure about your numbers? If the calculator is wrong and the floor is 6, then maybe that's what's going on. I'm guessing this is the point where I should keep in mind that the pool calculator is a set of suggestions and I need to adjust based on what I observe.

    I am SLAM'ing. I guess you are all over me because I said I was "shocking" the pool, but that's what I meant.

    Tangent . . . with FC < 5 so rarely a goal, too bad the easy tests stop there.

    - - - Updated - - -

    Quote Originally Posted by needsajet View Post
    Nice to meet you via TFP

    There's no real way to know the exact reason for visible algae and cloudiness, but the key right now is to SLAM the pool.

    This is the TFP procedure for the SLAM: Pool School - SLAM - Shock Level And Maintain

    The procedure needs to be followed thoroughly, and after that, you'll have better luck getting the water stabilized.

    Are you using muriatic acid for your pH adjustments?
    Yes, I use muriatic acid when I need to lower pH.
    15k gallon, IG plaster pebble surface, single speed filter pump, sand filter, Polaris 280 cleaner w/ PB40 booster, AutoPilot Nano+ w/ RC-28 cell.

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    needsajet's Avatar
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    Re: Rebalancing after conversion to SWG

    You're interpreting the recommended levels correctly. Some do use higher numbers quite successfully as well.

    There's no harm in the word "shocking" because it's a key part of doing a SLAM. Dropping pH to 7.2 before starting a SLAM, brushing regularly, and observing the endpoint criteria are just as important.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    jeffchap's Avatar
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    Re: Rebalancing after conversion to SWG

    Sorry, I forgot there is a separate CYA/FC chart for SWGs. I just always keep it my head: 7% of CYA as a minimum, 10% + 1 as a target, and 40% for a SLAM. I use those values even with my SWG, preferring to err on the high side.
    25000 gallon free-form gunite
    Jandy Stealth pump/CL340 cartridge filter
    Pentair IC40 SWG
    Pentair MasterTemp 250HD heater
    Jandy AquaLink RS automation

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