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Thread: White clumps at the bottom of the pool

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    White clumps at the bottom of the pool

    We are currently going through the most intense heat wave South Australia has ever experienced. At the moment, the temperature outside is 44.4 degrees Celsius ( 111.92 degrees Fahrenheit).

    Because of the high bather load and intense sunlight,I've been running the SWG pump and chlorinator at full blast for the last 2 days with no rest to keep chlorine levels high.

    I decided to give it a bit of a rest for an hour or so and found some white clumps had formed at the bottom of the pool.

    These formed at the end where the jets are located that deliver the chlorinated water back into the pool. The clumps covered an area of about 2 or 3 square metres. I tried to collect some with the net to examine them more closely but as soon as the net touched them, they disintegrated and converted to tiny white specks that just fell through the net.

    I noticed yesterday tiny white specks floating in the water as we were using the pool.

    Does anybody know what these might be? Could it be that there is way too much chlorine in the water? My testing kit only goes up to 5 but it seems there is much more in the water than that, as the water in the tester tuns almost blood red when I add the DPD tablet.

    Could it be slat? My salt levels have been pretty constant at 5000ppm. I have not added any more.

    I've tried attaching a photograph but I'm not sure if it will work (no idea what I'm doing)!
    Attached Images Attached Images
    Michael
    60,000 litre pool (15,850 gallons)
    Cartridge filter, SWG pool.
    In ground pool, tiled concrete
    Viron P320 eVo pool pump, 300 litres/ minute

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    Isaac-1's Avatar
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    Re: White clumps at the bottom of the pool

    Can you post a full set of test results, at least the best you can manage with a basic test kit, it might give us some pointers. Unfortunately without knowing your CYA level and your exact FC it is hard to know if your chlorine level is effective so it is hard to know if this is some type of algae growing in your water. Also what other chemicals have you added to your pool?

    Ike
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    Re: White clumps at the bottom of the pool

    Thanks Ike.

    I can give the following results:

    I get CYA tested every month. It was 30ppm 2 weeks ago.

    FC at the last test was 6.0 ppm but I suspect it's even higher now.

    PH is 7.6

    TA is 80

    Calcium hardness 189
    Michael
    60,000 litre pool (15,850 gallons)
    Cartridge filter, SWG pool.
    In ground pool, tiled concrete
    Viron P320 eVo pool pump, 300 litres/ minute

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    Re: White clumps at the bottom of the pool

    I suspect that these are calcium carbonate flakes that formed and sloughed off of the SWG cell plate when it reversed polarity. Perhaps running the SWG much longer had the pH rise and produced more of these flakes.

    If you can collect some of them, then if they are calcium carbonate, adding acid to them will make them fizz.

    However, your numbers give a low saturation index of around -0.5, at least in part due to the high salt levels but also none of your pH, TA or CH are particularly high. Then again, these sound like pool store numbers so they might be wrong.
    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
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    Re: White clumps at the bottom of the pool

    Pardon my ignorance Chem Geek, but what it a saturation index?

    Are my results not good?
    Michael
    60,000 litre pool (15,850 gallons)
    Cartridge filter, SWG pool.
    In ground pool, tiled concrete
    Viron P320 eVo pool pump, 300 litres/ minute

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    Patrick_B's Avatar
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    Re: White clumps at the bottom of the pool

    The SI is a formula that shows if you have water that is, or is not likely to create scale in your pool.

    According to those numbers, yours does not "seem" likely, but the numbers may be off. If they are pool store numbers there is a good chance they aren't accurate. We see that a lot with PS readings.

    One things is certain, it is NOT the FC causing that. It's likely salt or Calcium. If you can gather some, put a drop of your pool acid on it (Muriatic/Hydrochloric) and see if it reacts. If it does, then it's Calcium based, and likely Salt if it does not.

    The only way to know for certain what is happening with your pool is to have a good test kit, and run the numbers yourself. Being down under, the ones we suggest are much harder to obtain. If you search the forum, you can find where/how Aussies have found them to get shipped down there. Hope that helps.
    TFP Moderator
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    Re: White clumps at the bottom of the pool

    Thanks Patrick.

    If it's algae, is it harmful?

    Is it worth collecting a jar of it and getting it looked at (by whom in have no idea)?
    Michael
    60,000 litre pool (15,850 gallons)
    Cartridge filter, SWG pool.
    In ground pool, tiled concrete
    Viron P320 eVo pool pump, 300 litres/ minute

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    Re: White clumps at the bottom of the pool

    Get a small pile and put a drop or two of acid on the pile to see if it bubbles. Bubbles would indicate calcium carbonate (As previously noted). Also, if you remove the cell, you can check for scaling on the plates. If the plates are scaled, you can clean them with muriatic acid.

    The turquoise color indicates that copper is part of the compound. Possibly copper carbonate.

    Is there any copper in the pool, possibly from a heater or algaecide?

    The tile grout looks dark. Is that the original color?

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    Patrick_B's Avatar
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    Re: White clumps at the bottom of the pool

    No need to have it looked at. If you can get some, preferably let it dry, then we can see by performing the tests suggested.

    What about the test kit? Have one?
    TFP Moderator
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    Re: White clumps at the bottom of the pool

    The tile grout is the original color - the pool is only a few months old.

    It's very difficult to actually get some of the stuff for testing because it disintegrates as soon as you touch it. It's impossible to pick up with a net as it breaks into tiny specks that fall through the netting.

    I'll try to get some and let it dry to perform the tests you guys mentioned.

    I don't have the type of test kit you mentioned, Patrick, As you said, here in Australia they're hard to find. I'll search and track them down online. They sound pretty much essential.
    Michael
    60,000 litre pool (15,850 gallons)
    Cartridge filter, SWG pool.
    In ground pool, tiled concrete
    Viron P320 eVo pool pump, 300 litres/ minute

  11. Back To Top    #11

    Re: White clumps at the bottom of the pool

    Based on several factors, I think that the compound might be copper carbonate vs. calcium carbonate.

    The color seems to match copper carbonate more than calcium carbonate. The lack of physical integrity does not match calcium carbonate very well. And, the low CSI make Calcium carbonate less likely, but not impossible as the plates have a very high pH where the hydrogen gas is generated.

    Did you recently have algae? If yes, did you use a copper-based algaecide?

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    aussieta's Avatar
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    Re: White clumps at the bottom of the pool

    funny you mention that,
    i had a white dust covering the bottom of the pool a week ago, which i assumed was from using cal/hypo for a couple of days to slam pool
    i vacumed to waste and it didnt come back
    SWG inground peanut shaped eco-bright concrete pool
    50,000 litres 13,000 gallons
    Lincoln Salt Chlorinator, 25 gram cell Sand Filter with glass media
    Taylor K2006-C test kit, Taylor K-1766 salt test, Dolphin M500 pool cleaner
    are you taking care of your pool or is the poolshop taking care of you

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