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Thread: Partial Drain through through filter via skimmer and bottom drain connection

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    Join Date
    Mar 2015
    Location
    Sac-town CA
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    7

    Partial Drain through through filter via skimmer and bottom drain connection

    My CYA is >100. I don't even make it within 1/2" of the mark on my Taylor test kit before the black dot has disappeared. I opened the pool 2 weeks ago to a green mess, I couldn't see the deep end. I shocked it with Shockwave 73%, 4 lb worth of it over 2 days. The pool was ready to swim in a week later. I tested the water and verified the CYA test with the local pool store.

    I would like to drain it, but can't figure out how. I can get the water to pump out of the bottom of the filter without a problem, there's a hose bib attached there. Once the water is below the skimmer I start blowing bubbles and lose flow. At the bottom of the skimmer is the connection from the drain. There is a simple valve which covers the two ports so water only moves between the pipes and not from the skimmer. The pump pulls water at varying rates, sometimes coming to a stop. How do I drain the water without fear of hurting my pump?

    Please see the attached pictures of my equipment. There's no discharge to bypass the filter or heater I have to pull the water from the filter drain.
    2015-03-027.jpg
    22K gal plaster ig - 18x36x16x3-8 - Hayward 300 sqft cartridge filter - Sta-Rite Max-E-Therm 400 - Taylor K-2005 - Sac-town CA

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    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
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    Re: Partial Drain through through filter via skimmer and bottom drain connection

    That kind of diverter valve in the skimmer almost never forms a really good seal. Even a small air leak will cause the pump to lose prime.

    There are a couple of solutions. The simplest is to fill the pool at the same time you are draining it. This approach takes less total time, though it does use a bit more total water. Another approach that sometimes work is to use a cover pump or sump pump to pump water into the skimmer so that there is always some water to leak in, instead of air.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Mar 2015
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    Sac-town CA
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    Re: Partial Drain through through filter via skimmer and bottom drain connection

    Nice, thanks! It's some sort of consolation that there isn't a better way to do it, as is.

    Assuming I can keep the prime at the pump, would it be wrong to add a "T" between the pump discharge and the filter? I could add a valve that would help regulate the flow out, thus reducing the the pump sucking air. Keep the volume the same going in as out.... no slow downs to sucking air.
    22K gal plaster ig - 18x36x16x3-8 - Hayward 300 sqft cartridge filter - Sta-Rite Max-E-Therm 400 - Taylor K-2005 - Sac-town CA

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    jrs_diesel's Avatar
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    Aug 2014
    Location
    League City, TX
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    215

    Re: Partial Drain through through filter via skimmer and bottom drain connection

    The second method that Jason posted is what I did when I drained 14,000 gallons last summer after we moved in (I had high CYA too). Like he said, the diverter does not form a perfect seal once it shuts, so whatever is left slowly consumed by the pump. What we did was keep an eye on the water level in the skimmer, and scooped a bucket of water from the pool to keep plenty of water in the skimmer as needed. This way the pump did not suck any air.

    Do you have a pressure side cleaner line (for a Polaris cleaner)? If you do, you can increase your drain rate and shorten the drain time. We have one and I rigged up our vacuum hose to an extra pressure side fitting I had handy, and ran the other end of the hose to a cleanout fitting on the side of our house. Drained 14,000 gallons in about 5 hours.
    J.R.

    20K IG gunnite pool
    2HP Hayward single speed pump
    Cartridge filter

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    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
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    37,879

    Re: Partial Drain through through filter via skimmer and bottom drain connection

    Adding a "T" between the pump discharge and the filter is generally nice to have, but it won't help you keep the pump primed as you drain to any useful extent.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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