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Thread: Should I adjust?

  1. Back To Top    #1
    Alwayswantedapool's Avatar
    Join Date
    Jun 2015
    York SC

    Should I adjust?

    Readings from today

    Temp 40
    FC 8.5
    CC 0
    PH 7.5
    TA 70
    CH 50
    CYA 80
    CSI -1.31

    I am still on a journey to get CYA down, started at 180 so slowly but surely. But that means anytime I get a chance I am draining and refilling, typically with rain water. My target for FC right now is 9 and I will adjust today to get it back to 9.

    Last week the PH was 7.4 so I adjusted my returns to get some aeration and looks like over the week raised the PH from 7.4 to 7.5. Note, I think my pool is somewhat unique, my PH always trends down, not up.

    So I understand the CSI debate, and having a vinyl pool a negative number doesn't really hurt me I don't think.

    Playing with pool math, looks like bringing my CH up to around 200 puts me in a better spot from a CSI perspective. But, I am on a well with a CH of 30, so for the most part, my CH is going to naturally be lower.

    So the question is, thoughts on making any adjustments?
    I am thinking, just get my FC back up to 9 and leave the returns so I continue to aerate to bring up the PH. I was debating on adding some borax to bring it up to 7.6, but I don't think I need my TA to go up any.

    Appreciate the feedback.
    Mark, Pool: 30,000 gallon, IG Vinyl, Pentair Superflo Variable Speed 1.5 HP pump, Hayward S220T Sand Filter, Taylor k-2006 Test kit with speedstir. Dolphin Nautilus Plus.
    Hot Tub: Hot Spring Grandee 450 Gallons, Ace System (Salt water Chlorine Generator) Dichlor / Bleach method. Taylor K1766 Salt Test.

  2. Back To Top    #2
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Franklin, NC

    Re: Should I adjust?

    Your fine. With a vinyl pool, negative CSI doesn't mean anything. A negative CSI means the water will try to pull calcium out of the pool walls. On a gunite/cement pool this can be a problem because it will etch into the walls as it takes the calcium. Now, if your CSI were extremely positive, even with a vinyl pool you could get calcium scale forming on the vinyl.

    Here is a post from Chem Geek explaining:

    Quote Originally Posted by chem geek View Post
    The Calcite Saturation Index is about saturating the water with calcium carbonate. This is for pools where the water is exposed to surfaces that contain calcium carbonate such as pool plaster and grout in between tile. If you have a vinyl pool, then there is no need for such saturation so having a zero or low Calcium Hardness (CH) does not matter (see this thread for technical info about this).
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  3. Back To Top    #3
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Midland TX

    Re: Should I adjust?

    With those numbers I completely agree. Vinyl is extremely flexible in this regard.
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