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Thread: Calcium Hardness Constantly Decreasing! Why?

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    Calcium Hardness Constantly Decreasing! Why?

    I have a Gunite Pool. 28,000 Gallons. 20'x40'
    A little over a month ago I tested for CH & it was Low at 180. So I added 33 LBs of Calcium Chloride & that brought it up to 300. Now a little over a month later I tested again & it's back down to 180.
    I know how important Calcium is to a Plaster Pool. I have 2 small spots the size of a nickel where it looks like Plaster might have been eaten away.
    Yes, there has been rain here. But I don't think enough to lower that much. Why is my Pool constantly needing & eating up Calcium Chloride?

    Test Results:
    PH: 7.6
    TA: 80
    CH: 180 ???
    CYA 60

    Thanks in advance!
    20' X 40' Rectangular Gunite Pool with Spa
    28,000 Gallons
    Sand Filter
    Rainbow Chlorinator
    Penair Pump
    Polaris 280

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    Join Date
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    Re: Calcium Hardness Constantly Decreasing! Why?

    The only way I know of to have falling CH is a leak in the pool. Do you have to fill a lot?
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    duraleigh's Avatar
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    Re: Calcium Hardness Constantly Decreasing! Why?

    Confirming what robbieH says, CH never leaves your pool unless you are replacing the existing water with new water lower in CH.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Calcium Hardness Constantly Decreasing! Why?

    Yes, I do have some Leaks in Tile. About an Inch every 3 days. Is that considered a big leak?
    Thanks for the quick replies. That makes Total Sense. I did not think of that!

    I guess the leak has helped in another way though. My CYA needed to come down & it to is almost close to where it should be.
    20' X 40' Rectangular Gunite Pool with Spa
    28,000 Gallons
    Sand Filter
    Rainbow Chlorinator
    Penair Pump
    Polaris 280

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    Richard320's Avatar
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    San Dimas, CA (LA County)
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    Re: Calcium Hardness Constantly Decreasing! Why?

    Quote Originally Posted by dino1956
    Yes, I do have some Leaks in Tile. About an Inch every 3 days. Is that considered a big leak?
    Thanks for the quick replies. That makes Total Sense. I did not think of that!
    Let's see... with you dimensions and volume, your average depth is about 56". 3" is 5% of that.

    So you will lose about 5% CH every week. 5% CYA, too.....
    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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    Re: Calcium Hardness Constantly Decreasing! Why?

    That size leak for me adds up to a BUNCH of water to replace. You can fix it yourself if you know where the leak is with epoxy putty. If you don't, I highly recommend American Leak Detection if they are in your area. They will charge you less if you know for sure there are no leaks in your plumbing, as they won't have to do all those tests. If you aren't sure, it might be worth the investment to let them go for it.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    Re: Calcium Hardness Constantly Decreasing! Why?

    Richard, Thanks for the calculation!
    Yea Robbie, I'm running my Hose for 2-3 hours a week to compensate. I need to get this fixed.
    I don't really have any reason to be believe it's my Plumbing. There are like 5 Tiles with visible Gaps in them.
    I have a company in my area. And I just looked there is America Leak Detection in my area. Thank you both for the Info.
    20' X 40' Rectangular Gunite Pool with Spa
    28,000 Gallons
    Sand Filter
    Rainbow Chlorinator
    Penair Pump
    Polaris 280

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    Re: Calcium Hardness Constantly Decreasing! Why?

    A lot of the pool companies simply send ALD if you call them. Might as well go straight to the source.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
    If TFP has helped you, please click to SUPPORT TFP!

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    Re: Calcium Hardness Constantly Decreasing! Why?

    But will these guys fix leaks? Do they Install Pool Tiles, grout, etc...?
    20' X 40' Rectangular Gunite Pool with Spa
    28,000 Gallons
    Sand Filter
    Rainbow Chlorinator
    Penair Pump
    Polaris 280

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