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Thread: Figuring head presure on a 11k AGP

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    Figuring head presure on a 11k AGP

    Hi, I've been lurking around here for a few weeks reading and then did some more reading thanks to mas985. I am in the planning / buying stage of an 11k AGP which will be simi-buried 30". How would one go about figuring head pressure on a pool that is not yet built? I will be using a 120 sf c-filter and I would assume the pump/filter will be plumbed at the pool. Is there a general or average number to use for an AGP for determining what pump is best? I was thinking of using the Intelliflo vs as its rpm range/gpm can go as low as 20gpm which would get me a 10 hour turn over and I am not opposed to a 2 speed. Our electric rate is .12 kwh. I dont mind spending the money on an efficient motor but their is a point of diminishing returns. I've read that its better to have the water circulating for longer periods of time which will help keep the water healthy than to have stagnant water for longer periods. I guess all in all I am looking for a pump that I can have running for longer periods with the least cost to run.

    thanks
    Elliott

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    JasonLion's Avatar
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    Re: Figuring head presure on a 11k AGP

    Welcome to TFP!

    Why do you want to figure out the head pressure? That depends on so many different factors that you are unlikely to be able to do so. With a lot more information we could make a guess at TDH, but it really isn't worth the effort. What is it that you are actually trying to optimize?

    You almost certainly don't want to use an IntelliFlo on an above ground pool. Above ground pools have very low flow resistance, while the IntelliFlo is designed for fairly high flow resistance setups. Another point against the IntelliFlo is that it is very unlikely to pay back the extra upfront cost with electric rates that low.

    Quote Originally Posted by 71por914
    I've read that its better to have the water circulating for longer periods of time which will help keep the water healthy than to have stagnant water for longer periods.
    That isn't really true. As long as the pump runs at least once every 24 hours things will be fine. There are some very minor advantages to running the pump at more frequent intervals, so debris don't sink to the bottom of the pool, but the overall improvement is very small.

    Your best bet for saving money is going to be a small two speed above ground pool pump. A 3/4 HP two speed should be more than enough for that pool, if you can find one. Two speeds are sometimes difficult to find below 1 HP.
    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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    linen's Avatar
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    Re: Figuring head presure on a 11k AGP

    Quote Originally Posted by 71por914
    I will be using a 120 sf c-filter
    If you haven't bought the filter yet go for a cartridge that is a least 160 sq. ft. (or bigger).
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Figuring head presure on a 11k AGP

    Thanks for the welcome. The head pressure dilemma must have been my misunderstanding of what I thought was needed for the pump sizing. I think after going over some kwh numbers for the Dynamo it looks like I can get the pump run cost down to under $10 per month which makes me happy and just for the sake of someone else thinking about the VS pump it would take just over 8 years for it to pay for its self on our pool. The filter is not bought yet but Hayward suggested a 90sf c-filter which I thought was small. If I can find a bigger filter for a $1 or so p/sf I will buy it or just give me more time and I will probable talk myself in to a bigger one. O ya did I mention I'm a CSOB then again my moniker my have given it away.

    thanks again
    Elliott

    now on to the next search

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