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Thread: Suction not good during filter setting

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    Suction not good during filter setting

    I have a Hayward pro-grid DE filter

    Here is my problem. This pool was a mess chemically and cloudy when I started. I finally got the chemicals correct, but it was still very cloudy. Your forums gave me some clues. I checked the filter grids and found them to be in terrible shape. I replaced these, lubed the gasket, secured the filter cover good and added the correct amount of DE powder through the skimmer. As a note, the handle broke on the Hayward vari-flow valve, so I replaced the entire valve cover. I also lubed this well during install before tightening all the bolts. Also, I made sure the cover was in the same position as the old one when installing.
    As a result, the pool water is crystal clear. Now I need to clean the bottom.
    If I change the valve to backwash, the automatic vacuum works great. The pressure gauge shows it running at about 10lbs of pressure. When I switch to filter, the pressure goes up to about 20-25lbs and the suction is not as good. It isn't good enough to cause the vacuum to move about. I have emptied the skimmer basket and the basket under the clear cover near the motor. I also checked for leaks. I don't see any. I also don't see any air coming out of the returns or under the clear cover.
    I can't figure out what I am doing wrong. The pool is beautiful now except the bottom. Any advice you can give would be awesome.
    Also as a note- I didn't replace the spider gasket (it didn't look great) in the valve. Could this cause the problem listed above? The valve turns fine and I don't see it leaking at the backwater exit.



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    duraleigh's Avatar
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    Re: Suction not good during filter setting

    Sounds like your filter is clogged. When did you last backwash/clean it?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Richard320's Avatar
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    Re: Suction not good during filter setting

    STOP!!!

    If I change the valve to backwash, the automatic vacuum works great.
    When you do that, you are sending all the stuff you vacuum up inside the filter grids -the clean side - and blowing all the DE off the grids and out the waste pipe. You may have clogged the screens from the inside with bits of sand and grit and unless you recharged the DE afterwards, you might be clogging them up from the outside when you go back to filter.

    Simple test. What is pressure on filter? What is pressure on recirculate/bypass? If it's more than 2 psi, your grids are clogged.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Suction not good during filter setting

    I backwash it about 4 times a day until the pool water became clear. Now about twice a day.



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    Re: Suction not good during filter setting

    Filter- 25psi; backwash- 10psi, recirculate- 0psi
    I haven't added any DE accept when I replaced the grids last week. I took the grids out again this am to take a look at them. They looked well coated, even with the amount of back washing I have done. What should I do now?



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    Richard320's Avatar
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    Re: Suction not good during filter setting

    Quote Originally Posted by claystanley View Post
    Filter- 25psi; backwash- 10psi, recirculate- 0psi
    I haven't added any DE accept when I replaced the grids last week. I took the grids out again this am to take a look at them. They looked well coated, even with the amount of back washing I have done. What should I do now?


    Sent from my iPhone using Tapatalk
    They need to be scrubbed and blasted clean. The DE is what does the filtering. The grids just support the DE. Each time you backwash a DE filter you shouldmust add new DE.

    Use and care for DE filters
    DE Filter Cleaning Tutorial
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Suction not good during filter setting

    Even though they looked well coated this am? Is the blasting and scrubbing to clear out the trash I may have gotten inside the filters when I back washed with the vacuum on?



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    Richard320's Avatar
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    Re: Suction not good during filter setting

    Quote Originally Posted by claystanley View Post
    Even though they looked well coated this am? Is the blasting and scrubbing to clear out the trash I may have gotten inside the filters when I back washed with the vacuum on?


    Sent from my iPhone using Tapatalk
    When you backwash, all the DE should come off. In reality, it doesn't. But if you've been backwashing 4 times a day there shouldn't be any left on the grids. Yet there is. Which suggests maybe someone added clarifiers or flocculents or phosfree or some other miracle pool cure that gums up a filter. If you try recharging the DE without cleaning that off, you'l end up with this


    Those screens are just cloth. Should it take 10 psi to blow water through a piece of cloth? No, it shouldn't take any discernable pressure. They're clogged.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Suction not good during filter setting

    Ok. While waiting for your answer, I read through the info you provided links to about DE filters. I will degrease them and then acid soak and wash them after I spray them off.
    I AM a newbie to pools, so I'm sure I did everything wrong.
    After cleaning the filters, I understand I should have the suction to run the vacuum and clean up the bottom of the pool. And NEVER run the vacuum on backwash.
    There is ALOT of dead algae on the bottom. Is this going to reclog the filters requiring another cleaning? How often should I backwash and add more DE when I am vacuuming this much stuff?



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    Richard320's Avatar
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    Re: Suction not good during filter setting

    Quote Originally Posted by claystanley View Post
    Ok. While waiting for your answer, I read through the info you provided links to about DE filters. I will degrease them and then acid soak and wash them after I spray them off.
    I AM a newbie to pools, so I'm sure I did everything wrong.
    After cleaning the filters, I understand I should have the suction to run the vacuum and clean up the bottom of the pool. And NEVER run the vacuum on backwash.
    There is ALOT of dead algae on the bottom. Is this going to reclog the filters requiring another cleaning? How often should I backwash and add more DE when I am vacuuming this much stuff?


    Sent from my iPhone using Tapatalk
    You clean the filters. You add fresh DE. Vacuuming may clog the filters - that's what filters do: filter stuff out of the water. AFter the scrubbing and reassembly and adding the right amount of DE, you let things stabilize a few minutes and note the clean pressure. When it rises 25%, it's time to backwash again. And recharge again. If after you recharge it, it reads 8 psi, when it goes to 10, it's dirty.

    The other way to do it is to set the multiport to waste when you vacuum. Whatever you suck up with the vacuum won't go to the filter, it will go out the backwash line. You will be rid of the stuff for good, but you'll also lose a lot of water.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Suction not good during filter setting

    Followed the instruction. It's exactly as you said it would be. Thank you so much.



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