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Thread: Proper Drain/Skimmer Pressure Balance

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    MBMMPool's Avatar
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    Proper Drain/Skimmer Pressure Balance

    2nd Summer with my pool. Ever since install, I have operated things with all three of my return valves (Shallow Skimmer, Deep End Skimmer, and Main Drain) 100% open. Is this "Normal", or do people tend to try to "balance" for some optimum flow.

    I'm asking because (to me) my Main Drains (I have two drains- for Safety- that operate from the same "T" plumbing line) seem like they could/should have more suction than they do. I get sentiment close to the floor drains that doesn't seem to "suck in" like I think it should.

    Any thoughts appreciated. I'm an anal, pool- related Excel Spreadsheet wielding, mechanical engineer who just likes to know that "things are right". Thanks to this sight and BBB, my pool looks great and has truly been "Trouble Free" so far. [attachment=0:mzyw74hj]ImageUploadedByTapatalk 21373730733.492612.jpg[/attachment:mzyw74hj]


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    18x36' 25,000 Gallon IG Vinyl Pool
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    Richard320's Avatar
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    Re: Proper Drain/Skimmer Pressure Balance

    If you have dual drains and the proper anti-entrapment covers, you won't feel any suction. The main drains really don't do a lot except improve circulation and keep the water from getting temperature stratification. Even when I brush debris -light stuff, like flower petals - at my drain, it has to hit one of the openings straight on to get sucked in. Half an inch away is too far.

    Since you're an engineer...save some empty soda or water bottles and fill them with colored water until you get zero buoyancy. Then push them down in the pool and observe your water flow patterns. That ought to keep you busy for the rest of the summer, tweaking the eyeballs for perfect circulation.
    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.
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    MBMMPool's Avatar
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    Re: Proper Drain/Skimmer Pressure Balance

    Thanks- sounds like "all is normal." And, yes- playing with things to better understand my pool's actual flow sound like an intriguing way to spend some future Saturday. (Needs to be cloudier/cooler, though- no way I'm getting the wife & kids out of the water today.


    18x36' 25,000 Gallon IG Vinyl Pool
    Coverstar 3000 Pool Cover
    Sand Filter (S244T)
    AO Smith 2Green 1HP Two Speed Motor W/Timer
    Pentair IntelliBrite 5G LED Lights

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    mas985's Avatar
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    Re: Proper Drain/Skimmer Pressure Balance

    IMHO, optimum flow is maximum flow which is accomplished with all the valves open. In most cases with all the ports at 100%, the skimmers will tend have a little more flow rate than the main drains which is a good thing because as Richard points out, the main drain has limited effectiveness.

    But, if you are interested in spreadsheets, I have a few that you can play with (see signature).
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Proper Drain/Skimmer Pressure Balance

    I have a similar pool with a 2-speed pump. On low, I run with the main drain throttled down to 50% to get better skimming action while still fighting stratification and improving overall circulation.

    Even on high and 100% from the mains, they won't suck from the floor around them. That's normal.
    Current: 28,000G 18'x36' I/G AnthonySylvan Plaster; Waterway 60 sq.ft. DE Filter; 1.0hp x 1.65 SF Two-Speed (B2982) WhisperFlo; 2004-Present
    Previous: 40,000G 20'x40' I/G Koven unlined WWII salvage 5/8" marine steel; Lomart Stainless Sand Filter; 3/4hp Hayward SuperPump; 1946-2003 (managed by me from about 1964)
    Ancient Taylor K-2000, upgraded with Taylor CH, TA, and FAS-DPD, and TFT CYA tests.

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