Become a TFP Supporter Welcome to our new server and new forum software. Pool School
Results 1 to 17 of 17

Thread: Deep End Main Drain vs. Downward pointing Return

  1. #1
    Junior Member
    Join Date
    Oct 2011
    Location
    Richmond Hill, Ontario
    Posts
    5

    Deep End Main Drain vs. Downward pointing Return

    I am planning to install a new vinyl pool, 16'x34'x28' Full 'L', with an 8' deep end. Total approximately 25,000 gallons I believe.

    1 quote I've received includes 2 main drains installed 3' apart. Others have quoted no main drain and instead, included an additional deep end return pointed downward to sweep the bottom and assist with recirculation. Not really sure which way to go and looking for advice. I'm also planning for a Polaris 9300 cleaner - not sure if this impacts the decision.

    I'm in Ontario, Canada so I'll be closing the pool for about 6 months each year.

    Other info on the proposed pool:
    - Dell Ozonator
    - Offline Chlorinator
    - Cartridge Filter
    - 300,000 BTU heater
    - 1 HP pump
    - 4' Sheer Descent water feature in deep end w/ additional pump
    - 2 skimmers
    - 4 other returns in pool

    Thanks in advance for any help,
    Gio

  2. #2
    Senior Member
    Join Date
    Feb 2008
    Location
    Flower Mound, TX
    Posts
    5,169

    Re: Deep End Main Drain vs. Downward pointing Return

    Welcome to TFP!

    Unless this is an indoor pool, you don't need the ozonator. The sun gives you all of the UV light you need for free.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  3. #3
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    20,917

    Re: Deep End Main Drain vs. Downward pointing Return

    I agree with 257 -- ditch the ozonator.
    I'd also ditch the chlorinator and go for a swcg.
    Also make sure that filter is 300 sqft or bigger.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

  4. #4
    Administrator JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    34,658

    Re: Deep End Main Drain vs. Downward pointing Return

    Having a main drain is nice, but hardly essential. Main drains have advantages, but they are also are more likely to have problems down the road. As a general rule I recommend against main drains in a vinyl liner pool due to the small additional risk of leaks, but many people have them and love them.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. #5
    Junior Member
    Join Date
    Oct 2011
    Location
    Richmond Hill, Ontario
    Posts
    5

    Re: Deep End Main Drain vs. Downward pointing Return

    What are the advantages and disadvantages of a main drain vs. additional return?

  6. #6
    Junior Member
    Join Date
    Oct 2011
    Location
    Richmond Hill, Ontario
    Posts
    5

    Re: Deep End Main Drain vs. Downward pointing Return

    The ozonator I was planning for was a CD type. Most of the guys quoting are saying it's the way to go these days and it lowers the Chlorine concentration required. They also say that SWCG's are good but then you have to deal more with pH unbalance.

  7. #7
    Senior Member mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    6,471

    Re: Deep End Main Drain vs. Downward pointing Return

    Quote Originally Posted by cgio
    What are the advantages and disadvantages of a main drain vs. additional return?
    Personally, I don't believe that there is anything that a main drain offers over a lower return. A lower return will provide much better circulation than main drains due to the higher exit velocity. Plus main drains don't really keep the bottom any cleaner other than a few inches around the drain and they aren't very useful in sucking up debris pushed toward them since most now have a anti-vortex covers which have very small openings. A vacuum, auto or manual, is much better at keeping the bottom clean.

    Plus given the number of people that have had main drain leaks and the fact that they are the most difficult item to repair on a pool, I would avoid them. In fact, I would avoid all in-floor plumbing if possible.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study
    18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  8. #8
    Mod Squad Melt In The Sun's Avatar
    Join Date
    Oct 2009
    Location
    Tucson, AZ
    Posts
    3,844

    Re: Deep End Main Drain vs. Downward pointing Return

    CD-type or not, unless the pool is inside, ozone is just a waste of money.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

  9. #9
    Administrator JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    34,658

    Re: Deep End Main Drain vs. Downward pointing Return

    If you have a main drain you are less likely to have the skimmer(s) clog with leaves and the pump starve for water in the fall, since water can still come from the main drain. Main drains also make it completely simple to get good deep end water circulation. You can get good deep end water circulation in several other ways without a main drain, but it requires a moments thought and proper aiming of the return jets. With a main drain it doesn't require any thought at all.

    If you follow the water balance suggestions here you are very unlikely to have PH problems because of a SWG. 95% of PH problems with a SWG come from people who insist on keeping their TA too high, which causes the PH to drift. Lower your TA to more reasonable levels and there is no longer a problem (unless you have extreme levels of aeration, ie a negative edge pool or huge waterfall).
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  10. #10
    Junior Member
    Join Date
    Oct 2011
    Location
    Richmond Hill, Ontario
    Posts
    5

    Re: Deep End Main Drain vs. Downward pointing Return

    Great info, thanks everyone.

    Jason: I do plan on having a 48" sheer descent water feature. Would this change anything in your opinion?

  11. #11
    Junior Member
    Join Date
    Oct 2011
    Location
    Richmond Hill, Ontario
    Posts
    5

    Re: Deep End Main Drain vs. Downward pointing Return

    Would a main drain system help improve pump efficiency then if it prevents starving? Does it improve suction? This seems to be the only argument for or against.

  12. #12
    Senior Member mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    6,471

    Re: Deep End Main Drain vs. Downward pointing Return

    You can use side wall suction ports instead of a main drain to prevent the pump being starved of water so again, I see no need for a main drain and it just creates one more failure point. Also, with the bypass wall ports, there will be no difference in efficiency.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study
    18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  13. #13
    Senior Member
    Join Date
    Dec 2009
    Location
    Central Massachusetts
    Posts
    2,575

    Re: Deep End Main Drain vs. Downward pointing Return

    I have a sidewall suction on my vinyl pool. My builder hates main drains in the floor and prefers the side wall suction.
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

  14. #14
    Senior Member In the Industry

    Join Date
    May 2007
    Location
    New Brunswick Canada
    Posts
    396

    Re: Deep End Main Drain vs. Downward pointing Return

    Just some thoughts:

    Do sidewall suctions create a greater risk for hair being pulled into it? Young girls for example?

    Main drains are now plumbed together on larger lines then returns, water flow is greater with less pull and less chance of hair being sucked into it.

    Just curious as to what builders recommend and whether its due to costing over what is actually needed and should be installed. A friend of mine, has a 16 x 32 inground and his builder installed one main drain and its directly plumbed to the bottom of his skimmer, the only reason I see this being done is simple, cheaper for builder and more of a hassle for pool owner. If I had to do mine again, I would have main drain the way mine is, I can control water flo at pump with two 2" lines coming in, one from Skimmer and one from Main Drain. I would then insist the builder find out where the prevailing wind is, put a skimmer in its line and have another skimmer on the other side.
    Canada
    14 X 28 Inground Aquarite SWG, Waterfall
    Solar Panels, Goldline Aqua Solar Controller

    Proud to say I use BBB in my new pool company!

  15. #15
    Senior Member mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    6,471

    Re: Deep End Main Drain vs. Downward pointing Return

    If a bypass and float valve is used in the skimmer and side wall suction port, the side wall port should only be active if the skimmer is clogged or water drops below the skimmer so under normal conditions, there should be very little flow rate through that port. Plus you can plumb the side wall as deep as you want if it is a concern and they make anti-entrapment covers for those as well.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study
    18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  16. #16
    Senior Member
    Join Date
    Mar 2011
    Posts
    3,000

    Re: Deep End Main Drain vs. Downward pointing Return

    Note: Skimmer equalizer lines are considered submerged suction ports, and as such, they are required under the Virginia Graeme Baker Pool & Spa Safety Act to be covered with a compliant cover.

  17. #17
    Senior Member
    Join Date
    May 2010
    Location
    Sarnia, Ontario Canada
    Posts
    150

    Re: Deep End Main Drain vs. Downward pointing Return

    i have both...double main drain and lower return. not having the main drains should save you 3-400$ in parts...plus some in labor...should be quite a bit as I watched my pb fight watertable issues and it would have saved MANY hours not having the floor drains... i am not advocating for or against, i have not had my pool long enough to say, just that if you don't have the floor drains, a lower return would not be a "fair trade" dollar wise in my opinion

    ps...i have been working my 9300xi hard...i left the solar cover off for a few days and there happend to be 70km hr winds. i could not see half the bottom of my pool for all the leaves that got blown in. the 9300xi worked like a champ...i would have to pull her out every 20 min or so to empty the filter which was completely jammed...
    The big dig has begun! 20x47' double roman vinyl liner pool. Pentair EasyTouch 8PSC-IC40, Polaris 9300xi, Interfab Turbotwister slide, S.R. Smith T7 diving board with LED lit waterfall, 011018 Pentair IntelliFlo, Pentair Clean & Clear Plus Filter CCP420, Pentair 120V IntelliBrite LED, Cleardeck indeck solar reel, 530 sq' solar system vinyl-liner-pool-build-in-ontario-canada-new-pictures-t30213.html

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •