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Thread: How to Adjust PH after Pool Closed for Winter

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    How to Adjust PH after Pool Closed for Winter

    I have a one year old 18,700 plaster pool with a SWG so my ph always rises and needs to be knocked down every week. My pool was closed a week ago (I live in NJ) and out of curiousity I check the PH level after undoing a few straps to get to the water and the PH is now b/w 8.2-8.4. It was 7.6 when it was closed. My alkalinity is still 100. Is there anything I can do to adjust the PH and avoid scale problems in 8 months? Or am I stuck since I can't circulate the water. I heard muriatic acid will just sink to the bottom and scorch the plaster without the water circulating. Any ideas, much appreciated.

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    Join Date
    Feb 2008
    Denton, TX

    Re: How to Adjust PH after Pool Closed for Winter

    Well, first off, you can't really rely on your pH reading too much because you took the sample from water that wasn't circulating. The water really needs to be circulating for a while before you can reliably draw an accurate sample. Secondly, the temperature of the water makes a big difference when it comes to CSI or the potential for scaling to occur. When the water is cold, the environment is much less attractive for scaling to occur. For example, if your pH is 8.2, your water temp is 60, and your TA is 100, your CSI (scaling potential) is actually less than 0.6. This puts it in the ok range.

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    Re: How to Adjust PH after Pool Closed for Winter

    Thanks. That's a little comforting re the accuracy of the sample I took. I'm just concerned given the experience w the constant rise in PH weekly and the 8.4 does not seem that unreasonable to me, although surprising since it's been closed for a week. I have a solid cover as well. My water temp a week ago was around 65 and I have been using the Pool Calculator as well. If my Ph is 8.4, TA 100, CH 340, CYA 30, Temp 65 the calculator gives me a CSI of .85 which is scaling. When I plug in 8.2 to be conservative and a Temp of 60 the CSI reads .61, a little over scaling. It's suppose to heat up to 80 degrees the next few days and I had a huge problem with scale after the pool was closed last year for the first time and opened in May, so bad that the pool was drained and hydro sanded. I just don't want to experience the same problem again. I also put in 2 quarts of Jack Magic's Magenta in the pool when it was closed since I used this weekly for stain and scale prevention.

    Should I still be overly concerned with the .85 if the reading is correct? Thanks again.

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