Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 5 of 5

Thread: Conditioner-Stabilizer granules blowing back into the pool

  1. Back To Top    #1

    In the Industry


    Join Date
    Jul 2012
    Location
    Saugerties, NY
    Posts
    447

    Conditioner-Stabilizer granules blowing back into the pool

    I've noticed on several pools, two of them are brand new, that when I add CYA to the pool, small amounts of it blow back into the pool through the return jets. How is this possible? When adding CYA, I put it into the skimmer slowly with the filter set to filter. These are sand filters with multiports. I just don't understand how fairly large granules can pass through a sand filter, when extremely small particles like algae can be caught.
    TreeFiter

    Pool Technician
    Saugerties, NY

  2. Back To Top    #2

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: Conditioner-Stabilizer granules blowing back into the po

    They can't. Don't know what is happening with your pools but CYA doesn't pass through ANY filter if it was installed and working correctly.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

    In the Industry


    Join Date
    Jul 2012
    Location
    Saugerties, NY
    Posts
    447

    Re: Conditioner-Stabilizer granules blowing back into the po

    That is what I thought, but I've seen it happen a few times now. I would think if CYA passes through, sand would too, since they are similar in size. Only thing I can think of is maybe there is a poor fit where the multiport slips over the stand pipe. Sand is more dense so it doesn't swirl up that high, but maybe the CYA does? Whatever it is, its strange.
    TreeFiter

    Pool Technician
    Saugerties, NY

  4. Back To Top    #4

    In the Industry


    Join Date
    Jul 2012
    Location
    Saugerties, NY
    Posts
    447

    Re: Conditioner-Stabilizer granules blowing back into the po

    It turns out it wasn't CYA at all. And you were right that it can't pass through any filter. So I went to one of these pools today, and there was a lot of white granular material all over the bottom of this pool. I mean you would have to dump a 4lb bag of CYA right into the pool to have this much on the bottom. So right away I was doubtful that it was actually CYA. I vacuumed it up, and payed attention to the returns. If it blew through once, it should be able to come back in again. Nothing came through the returns, as should be expected of a functioning filter. I was able to sample some of the white granules from the pump basket. I put some in a small vial, and mixed it up with some pool water. If it were CYA, I should be able to get a high CYA reading on a test strip, but I didn't. It didn't feel like CYA either. It felt like sand.

    So I have a theory about what it is and where it came from. I'd love to hear what everyone else thinks. I believe I've discussed similar events on here in other posts, but this is what I think is going on.

    This tends to happen in new pools. Our new pools are filled with water that is trucked in from an underground lake. The underground lake is in an area where there is mostly limestone. So the water naturally has elevated pH, TA, and Calcium levels. The water is usually about 60 degrees when it is delivered. So of course we adjust the pH, and TA, and start up the SWG. Then we turn on the heater, because customers don't want to swim in 60 degree water. So we bring it up to about 80. Calcium Carbonate (limestone) is more soluble in cold water than in warmer water. So what I think happens is as water passes through a heater, Calcium Carbonate is being deposited inside the heater. It grows as scale inside the element would be my guess. So when we come along and add CYA to the pool, we pour it into the skimmer, where it dissolves and passes through the heater on its way back to the pool. So we have just run an acid over the Calcium Carbonate scale, which partially dissolves it and loosens it. These flakes of scale break free and blow into the pool through the return jets. So when a guy puts CYA into the skimmer and within a few seconds sees white flakes flying out of the return jets, they assume it is the CYA coming back out, but its actually Calcium Carbonate Scale. I would imagine the same sort of thing could happen if pH decreaser were added through the skimmer as well.
    TreeFiter

    Pool Technician
    Saugerties, NY

  5. Back To Top    #5
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: Conditioner-Stabilizer granules blowing back into the po

    If your theory is correct, it would be easy to prove. Collect some of these particles again, dry them, and expose them to Muriatic Acid. Just put a drop of acid on them, and if it is CaCo3 you will get a reaction.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •