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Thread: DE Filter Clogging and High Calcium Level

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    DE Filter Clogging and High Calcium Level

    I just found this forum a few days ago and am looking forward to spending lots of time here.

    First some background (maybe it is pertinent to my immediate problems):
    - 20x40 IG pool, approx 5 years old
    - vinyl liner
    - originally, we used Tri-Chlor pucks for 2 years and were constantly struggling with low PH. Bought a ton of borax. For 1 year, I used bleach (no PH problems) but found it to be a pain. Switched to Cal Hypo on recommendation from friends and multiple pool vendors. I now know that use of cal hypo has caused my pool to be inundated with calcium (see levels below).
    - i've been paying our pool installer to close/open the pool every year. The swear up/down/left/right that the DE grids are chemically cleaned every year. The guy has an excellent reputation so I want to believe him.
    - liner is light blue, and is wearing off. We first noticed this in year 2 when we used a cleaning robot for a month or so. We noticed that the robot wore off the pattern in the corners. We returned the robot, thinking it was the problem but over time we have noticed the problem everywhere. Not bleached, it is wearing off. The pattern can literally be scratched off with a fingernail. The pool installer says it is probably due to a bad liner but says the manuf warranty is worthless and that it is not worth trying to go back to them.
    - the first year we had the pool, the DE filter didn't require backwashing till the summer was 2/3 over. Since then, it has constantly been a PITA. With sparkling clean water, the filter is typically clogged a day after backflushing and within a week of being taken apart. Over the last several years, I let the pump run for a week or so in a low flow condition with clogged filter before backflushing.
    - This past weekend, I tore the filter apart (again) but this time I used a spray-on acid that is meant to clean DE filter grids. It sure did a job on the grass so I think that it worked. Unfortunately, when I got home this evening the filter was 12 psi over the "clean" pressure.

    Current chemical levels:
    FC-2
    TC-.5
    Alkalinity-120
    Calcium - 400
    PH - 7.6

    Is it possible that the high calcium level is causing the DE filter to become clogged so quickly? I am guessing that there is no connection (the filter was constantly clogged when using Clorox and Tri-Chlor pucks too) but I need to ask the question.

    Is a calcium level of 400 reason to panic and replace all of our water? From reading on this forum, I understand that there is no effective way to reduce calcium.

    Are there any other reasons why a DE filter would clog so quickly in water that appears clean?

    thanks!



    - As stated earlier, my DE filter is clogged within 1 day of being backflushed. This past Saturday, needed to buy more DE and again asked aboutI took the whole thing apart and used a chemical spray. It is

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
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    Re: DE Filter Clogging and High Calcium Level

    Welcome to TFP.

    I don't believe your calcium is the source of your filter problem.

    Any chance that you are using the wrong amount of DE, or the wrong technique when recharging your filter? Either too much or too little could potentially be an issue. Let us know what filter you have, pump size and how you recharge.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    JasonLion's Avatar
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    Re: DE Filter Clogging and High Calcium Level

    Welcome to TFP!

    Your CH levels aren't high enough to be causing problems for the filter just at the moment, though they are something to keep an eye on. CH at 400 is a little high, but it is easily managed by lowering the TA to compensate. I suggest you work on lowering your TA to around 80. You can do this fairly quickly by following these instructions, though lowering TA slowly simply by keeping the PH between 7.2 and 7.5 for a while will be good enough in this situation.

    In addition to what JohnT said, another possible reason the DE filter is clogging up so quickly is that the grids might need a good cleaning. You can do a through cleaning of the grids by first rinsing them off normally, then soak them overnight in a solution of one cup of automatic dishwashing detergent for every five gallons of water, then rinse again and soak in a mixture of ten parts of water for each part of muriatic acid for three hours, rinse one last time, and reassemble the filter.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: DE Filter Clogging and High Calcium Level

    I cannot get into my pool shed now....knocked down a wasp nest before coming inside! But, my memory tells me:

    Hayward DE filter (not the model with the bump handle)

    the filter calls for 6# of DE

    I have one of the 1# measuring cups that I used this past weekend to add 6# of DE

    I do not specifically remember the pump flow rate, but I definitely remember specifically checking to make sure that the flow was within the range recommended by Hayward

    I'll get the specific filter model and pump model tomorrow when it is safe!

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    Mod Squad JohnT's Avatar
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    Re: DE Filter Clogging and High Calcium Level

    Sissy! They are just little bugs!

    When filter grids get coated with oils and goop from swimmers and they are then acid washed, you can get a coating that is pretty well permanent that acid washing won't remove. Soaking the grids in dishwashing powder or TSP will remove the oils, which is usually enough to restore filter function, but if your grids were acid washed while dirty, you could be needing new grids.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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