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Thread: Do I need a main drain?

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    Do I need a main drain?

    Looking at getting a 16 x 32 vinyl liner installed. Builder is proposing 2 skimmers, 2 returns but no main drain. Pool will be 5' deep at deepest, with most of it being 3'6". They said they can put one in if I want.
    Please advise, Bob

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Do I need a main drain?

    Welcome to TFP!

    A main drain is nice to have, but not essential. They are often left off of vinyl liner pools. Each penetration of the liner is a potential leak. While it isn't at all likely that it would actually leak, the risk is a minor negative. Main drains also often end up getting clogged after many years. Still, having a main drain improves the circulation a little and gives you a place to sweep debris into.
    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

  3. Back To Top    #3

    Re: Do I need a main drain?


    I'm not a pool professional, just a home owner, but I reinstalled my main drain because they help circulate the water at the bottom of the pool and circulate the cooler water through your heat pump.
    I was told by one pool repair guy that I could seal up my drain and help the water movement with a pool robot.
    Cement 12'x30', in the neighborhood of 50 years old. Restored, 1.5"plumbing, 1hp super pump 2, Hayward swim clear cartridge filter, Summit2.5t heater,Hayward SWG t-9 cell, Nexxus Blanco lights, pentair bermuda gunite skimmer.

  4. Back To Top    #4

    Join Date
    Aug 2010
    Central Illinois

    Re: Do I need a main drain?

    I am also wondering the same thing. I have read about having low suction ports instead of a main drain. Anyone have any experience with these?
    DIY 18x36 Vinyl Liner 1Hp 2 speed super pump, Hayward Swim Clear cartridge filter, Pentair 12v Intellibrite 5G, MX8 suction pool cleaner.

  5. Back To Top    #5

    Join Date
    Mar 2007
    Coastalish 'down easter'

    Re: Do I need a main drain?

    Welcome to TFP!!

    You don't have to have a main drain but, as was pointed out, it helps with the lower water circulation.

    If the main drain line gets compromised, it's very hard to repair it, so usually it just gets plugged off.

    Low suction ports are an option, we installed them for 10 years on IG liner pools, but the grates and other compliance issues (for VGB) made us stop

    An alternative is to install a couple of low returns to 'stir up' the water at the bottom of the pool, which is better than no low drains, but not optimal.
    Luv& Luk

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  6. Back To Top    #6

    Re: Do I need a main drain?

    We have a main drain our pool and I'm glad we did it. It makes it nice when you want to do a quick manual vacuum to grab a few leaves in the bottom of the pool. We switch to full main drain for a few minutes, get the vacuum ready to go and then just vacuum what was pulled to the center. Great for when you only have a few minutes before people start coming and don't have time to let your automatic vac do the job for you. I also like it too for when we've had a minor algae bloom... turned the main drain on full and brushed the floor debris and dead algae toward the center drain.. made me feel like I was helping move it toward the filter anyway
    Indiana, ABG 24'x52" Galveston by Blue Cascade (Craigslist $600 w/part of deck included), 13,500 gallons, Intex SWG, solar panel

    My backyard is like a park... Why then does DH always want to go camping??? I just don't understand.

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