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Thread: Rising CH - Causes?

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    Rising CH - Causes?

    Hello

    It's been 5 months since we filled our new pool. Since then CH has been rising, which i gather is normal for a concrete pool. However, I tested my water the other day and these were the results:

    CH 400
    FC 6.5
    TA 50
    CYA 70
    PH 7.6

    The CH has risen by 100 since I last tested a month or so ago. We have had some hot weather recently and i have topped up the pool with water a couple of times since testing, our tap water has CH of 60. Is it possible that the fill water could have contributed to the rising CH that much.?

    I should say also that when i brushed the walls the day before doing the testing, a bit of dust came off the walls so I wonder if the calcium could be leaching from the walls? Also i noticed a small amount of white crusty build up in placed underneath the coping. We have an automatic acid feeder so the PH doesn't usually rise that much but i don't know how much acid it's putting into the pool though....
    33000L Concrete Pool, Viron P320 Pump, Viron-PH Auto PH Chlorinator, Viron CL400 cartridge filter, Sunlover solar heating, TF-100 Testkit and Taylor speedstir

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    Re: Rising CH - Causes?

    HI All

    After posting the above I saw another thread discussing this topic. After reading the topic I will plug my numbers and check the CSI and get back to y'all if i have any concerns
    33000L Concrete Pool, Viron P320 Pump, Viron-PH Auto PH Chlorinator, Viron CL400 cartridge filter, Sunlover solar heating, TF-100 Testkit and Taylor speedstir

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    Re: Rising CH - Causes?

    hi again
    \
    After plugging my numbers into the poolmath I See that due to the salt requirement for my SWCG (currently level is 3800) my CSI is actually quite negative anyway. In fact it looks like I should let PH go up a bit and raise TA, would that be correct?
    33000L Concrete Pool, Viron P320 Pump, Viron-PH Auto PH Chlorinator, Viron CL400 cartridge filter, Sunlover solar heating, TF-100 Testkit and Taylor speedstir

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    Join Date
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    Re: Rising CH - Causes?

    Yes, that is correct, but I'd go easy on the TA, perhaps only get it to 70 ppm since you don't want your pH to rise that much over time. Your pH might settle in at around 7.7 or 7.8 which is also fine.
    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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    Re: Rising CH - Causes?

    Thanks for that chem geek As for the rising CH do you think that a negtive CSI > 0.6 will cause CH to rise that quickly? or is it more likely evaporation + fill?
    33000L Concrete Pool, Viron P320 Pump, Viron-PH Auto PH Chlorinator, Viron CL400 cartridge filter, Sunlover solar heating, TF-100 Testkit and Taylor speedstir

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    Richard320's Avatar
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    San Dimas, CA (LA County)
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    Re: Rising CH - Causes?

    Quote Originally Posted by paulio View Post
    Thanks for that chem geek As for the rising CH do you think that a negtive CSI > 0.6 will cause CH to rise that quickly? or is it more likely evaporation + fill?
    CSI is just a number, an end result of some math; it's not an actual chemical value.

    My take is that you are losing water via evaporation but the Calcium stays behind. That said, it could also be testing error. That CH test takes a lot of mixing. Lots and lots. Even with the speedstir doing it for me, sometimes when the color is just about to change, running it another cycle without adding any more R-0012 will get it to turn for me. The alternative would have been to add another drop or two and have it change. My CH readings dropped dramatically just by switching the test from manual swirling to using the speedstir.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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