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Thread: Should the chemical balancing for closing be different than during swim season?

  1. Back To Top    #1

    Join Date
    Jul 2014
    Berks County, PA

    Should the chemical balancing for closing be different than during swim season?


    My pool store has often indicated to me that the balancing is slightly different for winter balancing. Basically what they have always had me do is to boost the calcium hardness up to a range between 200-275. I've gotten to the point recently (as is indicated in many of my recent threads) where I have started doing my own testing rather than relying on pool store advice. It does seem, from looking back at my store water test printouts, that by the time I was ready to close often my CH was well below 200. I have been reading some of the sticky notes here about closing and don't find anything indicating that the levels during winter should be any different than during summer. Thanks for any advice.

    12,000 gal. Anthony IG pool; 3 ft. shallow end to 6 ft. deep end; Built 1989; Renovated July 2014 using a 10-part unexposed quartz plaster aggregate of 3 S-grade Blue, 3 S-grade Gray, 2 T-grade Blue, 2 T-grade Gray; Apollo VA-52 DE Filter; Hayward SP-2607X10 Super Pump 1-HP Single Speed; Jandy AE-Ti Heat Pump; Taylor K-2006 Test Kit

  2. Back To Top    #2

    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: Should the chemical balancing for closing be different than during swim season?

    They may be saying to do this since the saturation index gets lower at lower temperature, but the pH usually rises and that is enough to compensate. The only reason to not just let the pH rise, say from 7.5 to 7.7 or 7.8, would be if you have metals in the water and are trying to avoid metal staining. Also note that any degradation of plaster will be a lot slower at colder water temperatures and that pH is the most important factor (unless the CH or TA are very low).

    So since the pH is easiest to change, I'd just adjust that. Then upon opening, you can increase CH if it's low since it may get diluted by winter rains or by the partial drain upon closing (I presume the latter for where you live).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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