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Thread: Is it possible my filter lets stuff back in my pool?

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    Join Date
    Aug 2011
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    Blanchard, Oklahoma
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    26

    Is it possible my filter lets stuff back in my pool?

    It only happens from time to time after I vac or switch the pump speed from low to high and even then not every time. I thought I had an issue with my filter last year and had the pool company come check it under warranty. They thought maybe it was letting some of the sand back through, but they dumped the sand and checked everything and replaced the sand. They couldn't find anything wrong and we couldn't get the problem to replicate while they were there. So I assumed everything was ok, I thought maybe I just get a lot of dirt from high winds here in Oklahoma. Then this year I open up to really clean pool. Water was clear with a little bit of dirt on the bottom. This weekend I was running the vac and was about ready to pull it out, so I shut the pump off. I then decided it had missed a couple of spots so I was going to manually hit those. When I turned the pump on I noticed the water was visibly darker for a split second coming out of the return. The spots I had missed were on the other side of the pool and I know the area around the return was clean before I moved the vac. After I got the vac out I noticed a couple of spots on the pool floor close to the return. I don't know what to do. Is there some other explanation for this? Please offer any advice you can. Thanks,
    30ft x 54in AGP 24,900 gallons
    400 lbs High Rate Sand filter
    2HP, 2 speed pump
    Pool Install April 2012

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    JasonLion's Avatar
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    Re: Is is possible my filter lets stuff back in my pool?

    Problems like this one are sometimes difficult to pin down. You might need to investigate a couple of possibilities before you find it.

    The symptoms you describe sound a bit like channeling. Sand filters can become channeled, which means that small open paths (channels) open up between the sand grains, allowing debris to pass through without being properly filtered. This is most common when the pump is too large for the filter. A 400 lb sand filter is fairly large, but so is a 2 HP pump. It is remotely possible that running the pump on high over years could cause channeling. How recently did they empty the sand out? Channeling would be cleared up by taking the sand out and then replacing it, and would take a while to occur again.

    It is also possible that something is broken in your main valve, allowing debris to bypass the filter entirely. A weak spring inside the main valve could possibly cause symptoms like the ones you describe.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Aug 2011
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    Blanchard, Oklahoma
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    Re: Is is possible my filter lets stuff back in my pool?

    Well the sand was replaced at the end of august, and the filter is just now a year old. So I think that would rule that out. How do I check the main valve? Another question would be if it is the valve how does that explain it only happening every so often? Thanks for the reply.
    30ft x 54in AGP 24,900 gallons
    400 lbs High Rate Sand filter
    2HP, 2 speed pump
    Pool Install April 2012

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    Vette's Avatar
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    Jul 2012
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    Ohio
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    Re: Is is possible my filter lets stuff back in my pool?

    It still could be channeling. Some people have had success lightly tapping on their filter with a rubber mallet while the pump is running. That can sometimes stir the sand up. Won't hurt to try unless you bash it too hard.
    11,700 gallon 21' round 54" deep all-resin AGP - June 2012
    Waterway 1HP 2-speed pump / 100 sq ft cartridge filter
    Hayward 150,000btu Natural Gas heater
    I use and recommend the TF-100 for testing

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    Mod Squad jblizzle's Avatar
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    Re: Is is possible my filter lets stuff back in my pool?

    You could always just do a deep sand cleaning when would remove the possibility of channeling.

    Just gently move a hose down around in the sand bed and let all the gunk float out the top of the filter. This will allow you to check for any clumping and resettle the sand bed.
    Jason, TFP Moderator
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  6. Back To Top    #6

    Join Date
    Aug 2011
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    Blanchard, Oklahoma
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    Re: Is is possible my filter lets stuff back in my pool?

    Forgive my ignorance, but wouldn't it happen a lot more frequently if it was channeling?
    30ft x 54in AGP 24,900 gallons
    400 lbs High Rate Sand filter
    2HP, 2 speed pump
    Pool Install April 2012

  7. Back To Top    #7

    Join Date
    May 2009
    Location
    Mn
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    198

    Re: Is is possible my filter lets stuff back in my pool?

    What brand is your sand filter? Does it look like a big ball?

    If you look back at my posts we had the same problem. We tried everything to fix it. We even went to a two speed pump...and running the pump on low, we had clear water. Turn it to high and all the junk blew into the pool.

    Not saying your situation is the same, but what we found was a sort of channeling. Where the water enters the filter from the multiport, there wasn't really an even "spray" of water over the sand. It just shoots out from one place. When we opened the filter without draining it, we saw it. When we drained the water out previously, it masked the problem because the sand would cave over the lateral. So, we could see that the lateral was exposed, hence why stuff always blew into the pool on high.

    We tried modifying the strainer looking thing under the multiport by zip tying a strainer basket (cut to size) from our old pump. Between that, adding more sand and running the pump on low, we were pretty good. We used a rover to clean and only put the pump on high for a brief bug sucking in the middle of the pool.

    Our filter was a waterway/ecokleer.
    24' Round Diamond Star, 54" wall height, 200sq ft sta-rite cartridge filter
    Dynamo 1hp 2 speed pump, 199k Rheem milivolt heater
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