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Thread: Make do with CH 900?

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    bbrock's Avatar
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    Make do with CH 900?

    Hi all. I have received so much great help from this site. With your help thus far, my pool is looking great. Tx so much.

    After my partial drain/fill, done simultaneously, my CH is 900 (down from 1500). I am currently in the process of bringing my TA down from a high of 180. Today it was 150. I am shooting for a TA of 60-70. With a CH at 900, I can still have balanced water if I keep my pH in line and reduce TA to 60-70. For reference, my CYA is 50, FC 7.5, CC 0.

    Is this an acceptable plan? No problems keeping CH @ 900 with balanced water, right? Pool Calculator shows that I can have a pH swing from approx 7.1-7.7 with a a TA of 60 or 70 and be balanced.
    19k gal IG plaster, built '70s, probably resurfaced in '80s-'90s; Blue Haven Hayward filter C4520BHMB (Filbur FC-1275 cartridges); Hayward MaxFlo sp2302 VSP 1.5hp; 6 solar panels 288. sq. ft. total (142"x47.5" ea.) on 1 story hm; Pentair Compool LX220 Solar Controller; FlowVis flow meter; Maytronics Dolphin S200; AG 300 gal AquaTerra spa; TF-100 & Speedstir; gone: Pentair Challenger 3/4 HP 1 speed; Polaris 280

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    Mod Squad JVTrain's Avatar
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    Re: Make do with CH 900?

    It looks like you have a good handle on Pool Math and that CSI is a rather important number with plaster pools, especially with high levels of CH. You should be able to manage it. It's worth trying for a while to see how it goes and if you're having troubles keeping the pH stable in that range you can address it then.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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    JasonLion's Avatar
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    Re: Make do with CH 900?

    Yes, CH at 900 can be managed. Your plan is reasonable, though I would use an upper limit on PH of 7.6 to give yourself a little more safety margin. The key thing is to watch the PH. As long as you are methodical about that things should be alright.

    CH up to roughly 1200 can be handled this way, though eventually you get to a point where there is no choice but to replace water.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    bbrock's Avatar
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    Re: Make do with CH 900?

    Great you two. Tx.

    With regards to lowering my TA, I assume it's okay to keep lowering it to 7.0, vs. 7.2, even though the prior gives me slightly unbalanced water temporarily per Pool Math?
    19k gal IG plaster, built '70s, probably resurfaced in '80s-'90s; Blue Haven Hayward filter C4520BHMB (Filbur FC-1275 cartridges); Hayward MaxFlo sp2302 VSP 1.5hp; 6 solar panels 288. sq. ft. total (142"x47.5" ea.) on 1 story hm; Pentair Compool LX220 Solar Controller; FlowVis flow meter; Maytronics Dolphin S200; AG 300 gal AquaTerra spa; TF-100 & Speedstir; gone: Pentair Challenger 3/4 HP 1 speed; Polaris 280

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    JasonLion's Avatar
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    Re: Make do with CH 900?

    PH below 7.2 causes eye irritation for some people. Other than that, PH at 7.0 is fine in this situation.
    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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