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Thread: Why is my pressure so low?

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    Why is my pressure so low?

    I have a question, but haven't figured this site out totally yet. why , if the impellors arent clogged and i have good flow in a de filter, would I only get about 7 lbs of pressure? could it be too little or too much de?
    AG, 18' round 4' depth, 7647 gal, Hayward Power-Flo LX Series 1 hp pump w/ 85 sq ft cartridge filter

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    benavidescj's Avatar
    Join Date
    Apr 2010
    Fleming Island, FL

    Re: What we need to know to answer your questions

    Hi Davepags and welcome to TFP

    Here at TFP there are many different topics where you can post your questions. This particular question you ask is related to our topic section called "Equipment - Build, Use, and Repair". In that section there is a subsection called "Pumping Station". You get to the topic section by going to the main TFP website. At the top you will notice a white bar and in that bar is a link labled "Board Index". Click on board index and scroll down a bit and you will see the sections I am refering to. You can ask this question there if you wish or wait till a moderator comes along and moves your post. It won't take very long.

    Again, welcome!
    Pool: 28,000 gallons IG; IC 40 SWG; Pentair 120 gpm cartridge filter; Marble finish; Pentair Wisperflow 1.5 hp; Polaris 360
    Spa: 350 gallon; Bromine
    How to shock your pool

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    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana

    Re: Why is my pressure so low?

    Welcome to TFP.

    Two possibilities come to mind. First is a bad pressure gauge. They aren't very dependable. Second is a lack of water coming into the pump. Is the pump strainer basket full with no bubbles?
    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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    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    SouthWest Alabama

    Re: Why is my pressure so low?

    And third, a huge filter and a small pump. Your pressure could be perfectly normal for your system.

    We really need to know more about your equipment and layout do determine if there is a problem.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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  5. Back To Top    #5

    Join Date
    Mar 2010
    Spring, TX

    Re: Why is my pressure so low?

    When I clean my filter by backwashing, mine drops down between 0-10, so around 5-7. When I did a total take apart and clean of my DE filter, I got down around 4.
    13,000 Plaster IG Pool approx
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    Emerson 1081 EB653 1.0 HP 1.40 S.F. 3450 RPM
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    Re: Why is my pressure so low?

    Quote Originally Posted by mynewpool
    When I clean my filter by backwashing, mine drops down between 0-10, so around 5-7. When I did a total take apart and clean of my DE filter, I got down around 4.
    Yes, exactly. I have a 3/4HP pump, and a 65sqft DE filter. Normal running pressure is about 10PSI, and I bump it at 15. If I manually clean the filter tubes and reassemble, it will get down to 5psi.
    17,000 Gallon plaster pool. Hayward Perflex EC65 DE Filter. 3/4 HP Hayward Superpump converted to dual speed. CircuPool RJ45. Skimmer, floor drain, two returns.

  7. Back To Top    #7

    Join Date
    Aug 2009
    North Central Texas

    Re: Why is my pressure so low?

    I'm using Aqua Pearl, similar to DE but without the silica, in my big Quad filter, 80 sq ft. It is backwashing out better than cellulose did. When I backwash and run pump on the usual, 19-20 gpm, which is pretty low flow, after backwashing the psi is 3-5. When I take filter apart and clean, it is just a little under 3. If I increase the pump speed psi is higher than that and goes up as I run the pump faster. Any of the three common filter media for a DE filter, cellulose, DE, or Aqua Pearl, all give a just below 3 psi when the filter is opened and cleaned when filtering at 19-20 gpm.

    I'm not sure what the ball park figure would be in terms of comparing the 10-20 gpm to a certain HP, and/or fixed speed pump. I do not have very high head on the system.

    1981, 25K, IG, Blue Plaster 1996, somewhat oval, widens a bit at shallow end, 1.5" pipes, 2" at Pad, 1 separate main drain, 1 skimmer, 4 returns + dedicated cleaner return, 10 ft deep end with very fast decline from shallow, Pentair Quad 80 DE, Pentair Intelliflo VF, 3/4 HP Booster Pump (equipment pad about 8 ft below top of pool), Challanger 3/4 Trash/Emergency Pump 120v, Polaris 280 (pressure), iRobot Verro cleaner (robotic), Aquabot Turbo (robotic), Jacuzzi Tracker 4X (vacuum) Pool Blaster (Buster), Two (2) PoolSkims, Solar Breeze (solar powered top skimmer) (beta to ver. 2, release date 2010), ColorSplash LED replacement bulb. Aries 550 gal separate spa, 2002 (our 3rd and BEST spa) , BBB-Bromine

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