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Thread: Pump size advice needed

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    Pump size advice needed

    I'm building a new inground vinyl pool and I'm not sure on the pump and pipe size needed. The main drains will be 90 ft from the filter and 1 of the 2 skimmers a little farther than that. I'm planning 1.5hp single speed and 1 1/2" flex PVC. I'm assuming that 1 1/2" pipe would still be okay, but do I need to up size the pump for the distance?
    Under construction - Inground Vinyl Lagoon 18x36x28; 3ft-8ft depth; 107' perimeter; 24K gal; waterfall; Pebble bond finish perimeter decking

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    Mod Squad JVTrain's Avatar
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    Re: Pump size advice needed

    While I'm not well versed enough in pump sizing to give you a great answer, you'll gain A LOT more in flow and decreased head loss if you were to go with 2" piping versus upsizing the pump.

    I would also strongly consider going with a two speed pump so you can save on your electric bill.

    You might get more complete answers from other experts on pump sizing but you can try on this thread for size but it's a lot to take in: Hydraulics 101 - Have you lost your head? Personally, I think it should be called Hydraulics 101-301...
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Pump size advice needed

    Using 2 inch PVC would make a huge difference at a minimal cost. For the pump, you should consider a VS or at least a two speed pump. VS pumps cost more, but give you so much more flexibility. You can fine tune the speed for any application, and should you add solar heating or make other additions in the future, no problem.

    I'm running a 3 hp VS pump, but it seldom runs at a speed that draws more than 150 watts. Up front cost is higher, but long term operating cost makes up for it. Especially when you consider flexibility.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    Re: Pump size advice needed

    FWIW, for my pool built in 1978, all the suction lines are 2" but all the return lines are 1.5". I guess that was done 'back then' to create some back-pressure. Were I building it all over again, I'd just do 2" all around and call it good.

    And VS pumps are all the rage these days...very flexible in how you can use them for various things.
    ----Chris----
    25k IG/Spa Figure 8, 18x36, Pebble Sheen Blue Granite, Sta-Rite S8M150 Cartridge Filter, Pentair 460805 400k BTU Heater & 011018 IntelliFlo VarSpd
    Liquidator, Fafco Solar Heat, Polaris PB460 Booster Pump w/280 cleaner, Katchaleaf Cover, TF100 Test Kit, FAKE MAIN DRAIN

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    Re: Pump size advice needed

    Thanks for all of the good info. If it was a perfect world think of all the wonderful choices we could make. But upfront cost is a big factor at this point. I decided to go with the 1.5hp Pentair SuperFlo with 1 1/2" piping. Pumps that connect up to 2" piping are just too far outside of the budget.
    Under construction - Inground Vinyl Lagoon 18x36x28; 3ft-8ft depth; 107' perimeter; 24K gal; waterfall; Pebble bond finish perimeter decking

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    Mod Squad JVTrain's Avatar
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    Re: Pump size advice needed

    Quote Originally Posted by RoadTrip View Post
    Thanks for all of the good info. If it was a perfect world think of all the wonderful choices we could make. But upfront cost is a big factor at this point. I decided to go with the 1.5hp Pentair SuperFlo with 1 1/2" piping. Pumps that connect up to 2" piping are just too far outside of the budget.
    That pump you bought can be connected to 2" piping. Nearly any pump can be. The adapters that go onto the pump are specifically designed to have either 1.5" pipe slip inside the fitting, 2" piping slips on the outside. Did your builder tell you that it could not be?
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Pump size advice needed

    Quote Originally Posted by JVTrain View Post
    That pump you bought can be connected to 2" piping. Nearly any pump can be. The adapters that go onto the pump are specifically designed to have either 1.5" pipe slip inside the fitting, 2" piping slips on the outside. Did your builder tell you that it could not be?
    I'm the builder

    I didn't think of that. I'll look again at using the 2" with this pump.

    Thanks
    Under construction - Inground Vinyl Lagoon 18x36x28; 3ft-8ft depth; 107' perimeter; 24K gal; waterfall; Pebble bond finish perimeter decking

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    Mod Squad JVTrain's Avatar
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    Re: Pump size advice needed

    Quote Originally Posted by RoadTrip View Post
    I'm the builder
    Haha. Gotcha! Learn something new every time you ask a question around here sometimes. 2" rigid PVC is preferred over flex PVC. Properly installed, rigid PVC will last longer. Flexible PVC can be vulnerable to pests/sunlight. That being said, the pool that came with my house has 1.5" flexible PVC at least starting at the pad area, not sure what's below ground further away. Both skimmers and at least 1 return have been repaired due to leaks (previous owner).
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Pump size advice needed

    Quote Originally Posted by JVTrain View Post
    Haha. Gotcha! Learn something new every time you ask a question around here sometimes. 2" rigid PVC is preferred over flex PVC. Properly installed, rigid PVC will last longer. Flexible PVC can be vulnerable to pests/sunlight. That being said, the pool that came with my house has 1.5" flexible PVC at least starting at the pad area, not sure what's below ground further away. Both skimmers and at least 1 return have been repaired due to leaks (previous owner).
    The pool is all curved and the main drain is on the opposite end of the pool from the equipment. Plus I can get the flex in 50ft lengths so fewer joints underground to worry about. Water travels through curved pipe allot better than 90 degree, or even 45 degree, turns. My backwash to get to the front yard and the sewer access is going to run 100' UGH!!!

    I plan to pipe each inlet and return individually and manifold them with valves at the pump. I'll be using solid for everything above ground.
    Under construction - Inground Vinyl Lagoon 18x36x28; 3ft-8ft depth; 107' perimeter; 24K gal; waterfall; Pebble bond finish perimeter decking

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    Re: Pump size advice needed

    With rigid PVC, the maximum flow through an 1.5 pipe is half that of a 2 inch. With the additional friction coefficient in flex pipe it's even worse. There might be a bit more labor, but the durability and function of the system will be much better using rigid PVC, and I'll bet it won't cost any more than the 1.5 flex you were planing.

    If your budget won't cover a VS pump, at the very least use a two speed pump. It will pay you back for the extra cost in about a year.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    Re: Pump size advice needed

    I decided to nix the flex pipe and go with 1.5" rigid with a single 1.5HP Pentair Super Flo pump. I'll use a flow control valve on the return to the waterfall to control volume.
    Under construction - Inground Vinyl Lagoon 18x36x28; 3ft-8ft depth; 107' perimeter; 24K gal; waterfall; Pebble bond finish perimeter decking

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    Mod Squad JVTrain's Avatar
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    Re: Pump size advice needed

    Good luck with the project.

    Also...
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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