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Thread: Test numbers after a calcium scale problem

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    Test numbers after a calcium scale problem

    I opened my pool this year to find a massive scale problem, but I did two no-drain acid washes and the surfaces have pretty much returned to normal. I had the water checked at the pool store (I also did it myself but got some funny numbers) and here are the results (followed by the Pool School numbers for SWG pools)

    FC 3 (poolschool = 3)
    CC 0
    TC 3
    pH 7.4 (poolschool = 7.5-7.8)
    TA 175 (poolschool=60-80)
    CH 225 (poolschool = 250-350)
    CYA 40 (poolschool = 70-80)


    The obvious outliers are TA which is about 100 points higher than it should be, CH which is 25-100 points low and CYA which is about half of what it should be.

    Since the test was done, I've added some CYA that I had from last year to bring it up, so that number should be back in the proper zone pretty soon.

    My questions are, what should I do about the high TA and the low CH?

    Another question is about adding "scale inhibitor". The pool store guy recommneded adding 8oz every few weeks, but I'm wondering if that's really necessary since there is no more scale and I'm keeping the ph low.

    Thanks!
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

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    Re: Test numbers after a calcium scale problem

    PS - I just read the Pool School post about lowering the TA, but I don't have adjustible return jets so I can't aerate it that way. Is there another way?
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

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    Mod Squad Bama Rambler's Avatar
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    Re: Test numbers after a calcium scale problem

    Given that you have had a scaling problem I'd actively work on the TA issue. Aerate to bring the pH up to about 7.4 and then add acid to bring it back down to about 7.0 (don't go below 7) until the TA is closer to the recommended range.

    Do you have a water feature? If so use that. If not, rig a makeshift way to aerate. You could use a pipe sticking in a return, or a sprinkler head rigged to a return.

    You can go ahead now and add some CH if you really must but as close as you are to the range I'd just leave it alone.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Test numbers after a calcium scale problem

    Thanks Dave! I'll try to rig up some type of aerator.

    When you say "add some CH if you must" what do you mean?? Two part question actually.....

    1) Why do you say "if you must"? I'm only asking because it's what the Pool School tells me to do. (as you probably guessed, I'm a novice pool owner and in over my head. Ba-dum-bump!)

    2) What is CH? The pool calculator told me to add 226 oz of calcium chloride or 507 oz calcium chloride dihydrate. Neither of those sound like CH to me!

    If I do go this route is one better or more available than the other?

    Thanks again!
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

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    Mod Squad Bama Rambler's Avatar
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    Re: Test numbers after a calcium scale problem

    1) As close as you are I personally wouldn't worry about it.

    2) CH is calcium hardness, You raise CH by adding calcium in the form of Calcium Chloride or Calcium Chloride Dihydrate.

    It varies by location, some have one readily available and some places have the other. It really doesn't matter as long as you account for either.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Test numbers after a calcium scale problem

    Thanks again Dave!
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

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    Richard320's Avatar
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    Re: Test numbers after a calcium scale problem

    I wouldn't add any Calcium. You've had problems in the past with scale - how'd all that Calcium get in there? Did you add any? It doesn't sound like it; you're unfamiliar with which product to use. CH will rise all by itself through evaporation and refilling. At amazing rates, too, once things heat up. Trust me on that!

    Buy yourself an extra couple weeks not worrying about scale, don't add any CH.
    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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