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Thread: Adding Borax makes DE filter clogged.

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    Question Adding Borax makes DE filter clogged.

    hi,

    This year I am trying to add in Borax to increase the borate level of the pool. I choose a slow way of doing it, adding several box of borax per day and use muriatic acid to balance any PH change. I tried different ways of adding in Borax. Based on the pool calculator, pour in correct amount of acid first, and wait for 30mins. 1st way. try to dissolve the Borax powder in a bucket of water as much as it can, then slowly pour it into the skimmer. 2nd way dissolve and pour it directly into the pool. 3rd way, pour the powder directly into the skimmer. No matter how I did it, after a short time period, (<1 day) the DE filter pressure increases by 10psi (from 20 to 30psi) and no water flow from the return line any more. Whenever I see it happens, I shutdown the pump, let it idle for several minutes, then restart the pump. Again, at the first several minutes, the water flowing back from the return line and after a while, no return flow again. In this case, I am forced to do backwash or open the filter to clean.

    This really bothers me a lot. I searched online, seems like nobody ever had this issue before. My theory, which may not be correct is that Borax cannot be fully dissolved, since I always see there are very tiny crystal residue which cannot be dissolved in the water. These crystals clog the DE filter and I have to keep backwash it after this happens. btw, I started from a very clean grid (water cleaned and submerged in 1:6 muriatic acid for 18 hours. so it shouldn't be the filter issue.)

    I don't know if anyone has the same experience as mine. Does my theory make sense? finally, What's the best way of adding in borax without clogging the filter or it cannot be avoided at all?

    thank you.

  2. Back To Top    #2
    MikeInNH's Avatar
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    Re: Adding Borax makes DE filter clogged.

    Certainly don't pour it into the skimmer. I think I poured some into a nylon sock I borrowed from my wife then hung the sock in front of the return. The same way I add stabilizer.
    Mike
    2007 1st full year with AG pool~15k gallons 18'x33' JW
    6/2010 added 2 button Intex SWG-painless except for when reset
    Switched to BBB from Baquacil (couldn't pay me to go back)

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    Mod Squad zea3's Avatar
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    Re: Adding Borax makes DE filter clogged.

    Just broadcast the borax into the pool and brush well. It will dissolve fairly quickly. You would have to dissolve very small amounts in a bucket to be able to add it through the skimmer.
    TFP Moderator
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    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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    JoyfulNoise's Avatar
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    Adding Borax makes DE filter clogged.

    Dissolving borax in a bucket of water and adding it to the skimmer is a BAD idea. Borax will raise the pH of the water in that bucket to well over 9 and, depending on how much calcium hardness and TA you have, it will cause calcium scaling. That scale will likely form on your DE grids and completely block them up. You should follow the directions as-posted on this site for properly adding borates as they are designed to deliver the best results without problems like these. If your water has high CH then you should consider purchasing boric acid as it will work much better.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Adding Borax makes DE filter clogged.

    Thank you all for your quick replies.

    Yes. My 2nd way is to dissolve into a bucket and pour them (dissolved and not-yet disolved) all into the pool instead of through the skimmer. But even that, I got the same situation. Is that possible that the not-yet dissolved crystals were sucked in to the filter through the main drain at the bottom of the pool, before I brush them well?

    Fortunately, my CH level is not high, actually pretty low so far. I plan to leave CH to the end to adjust after borax.
    20'x 40' 32000 gallon pool. (built approx in 2001.)
    Vinyl liner (replaced in 2017)
    Pentair FNS Plus 48 DE filter
    AutoPilot Salt Chlorine Generator.
    Pentair Whisperflow pump w/ Variable Speed V-Green 165 Pool Pump Replacement Motor

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    Mod Squad zea3's Avatar
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    Re: Adding Borax makes DE filter clogged.

    Unless you have a whirlpool going at your main drain it would not suck all the borax into the filter.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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