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Thread: Should I install a flow meter to my new install?

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    Should I install a flow meter to my new install?

    I'll be piping an AG 18' round pool with 2" pvc instead of 1.5 flex. The 2" flow meters I've seen start at 40gpm reading. That seems low for my pool. Not that I would need less than 40gpm, but it starts there and goes to 120 or so, I forget. It is a high number though. The 1.5 size starts at 20 gpm.

    So should I stick one on there for the heck of it? I'm sure it would help, right? No idea why as of yet.

    Any recommendations? I'd like a nice one. Maybe digital.

    and shiny. thanks
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    H2O_Keeper's Avatar
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    Re: Should I install a flow meter to my new install?

    Try this link for a good start. Also see the following pages before/after this one:

    http://www1.mscdirect.com/CGI/NNPDFF?PM ... T4TP=*LTIP

    Just a thought though....If you capture your input vacuum and output pressure you can calculate your GPM. Then you can let your pressure gauge be your compass for GPM. Buy a good pressure gauge instead???
    21K Gal, IG, Vinyl, Bleach-Borax-Baking Soda, 3/4HP Hayward pump, Hayward sand filter, 200,000BTU Heater, TF100 Testkit
    "All that we are arises with our thoughts." - Buddha
    “When fate hands you a lemon, make lemonade.” - Dale Carnegie

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    Re: Should I install a flow meter to my new install?

    Quote Originally Posted by H2O_Keeper
    Try this link for a good start. Also see the following pages before/after this one:

    http://www1.mscdirect.com/CGI/NNPDFF?PM ... T4TP=*LTIP

    Just a thought though....If you capture your input vacuum and output pressure you can calculate your GPM. Then you can let your pressure gauge be your compass for GPM. Buy a good pressure gauge instead???



    OK, you lost me after "Just a thought though...." I think the filter I purchased has a pressure gauge on it. How good it is, I don't know. I doubt it's a quality one. Everything else you said... I have no idea about. Thanks though, for your reply.

    So, if I have a decent pressure gauge, I should be good to go? $700+ on that first page was enough for me to read. Maybe I'm overreaching. I should have went with the Pentair VF oump and got my flow meter that way. Darn this pool parts buying stuff and toys and things and gadgets business!!
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    JasonLion's Avatar
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    Re: Should I install a flow meter to my new install?

    There isn't any real need for a flow meter. If you want a nice toy they can be fun for a little while. In most situations that is all a flow meter is, a nice toy. Occasionally, particularly when you have a variable speed pump, or an especially complex setup, a flow meter is important to have, but normally it doesn't make any difference.

    The Blue & White 300 series flow meters are inexpensive and of reasonable quality. If you really want a flow meter you should be able to find one of them that is suitable for your setup.
    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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    Re: Should I install a flow meter to my new install?

    OK I see one there for $445. Looks nice. I wonder if it would help me. It's a 2" size.

    Now to those 'Pressure gauge' thingies. They are called thingies, right? jk.

    Seriously though, $45 seems a bit much. i figured $150 would be tops for my budget if it would help. I don't want to plumb everything, only to have missed the opportunity to install a meter in there. thanks again.

    **Edit** Sorry J-lion, didn't see your post until I posted the above. thanks!
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    H2O_Keeper's Avatar
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    Re: Should I install a flow meter to my new install?

    Sorry for the leap, see this link in pool school:

    hydraulics-101-have-you-lost-your-head-t915.html

    Read the Plumbing Head Loss section. You can then use this number for head against your manufacturers flow curve and their chart will tell you your GPM. A little research involved but a lot cheaper solution.

    Yep, you have to go industrial quality for something like this and its gonna be at least a few hundred dollars for a cheap one for a 2" pipe setup.

    Only suggestion if you want to upgrade your factory filter gauge is to get one with fluid in it, they help absorb the shocks in your system, thus last longer.
    21K Gal, IG, Vinyl, Bleach-Borax-Baking Soda, 3/4HP Hayward pump, Hayward sand filter, 200,000BTU Heater, TF100 Testkit
    "All that we are arises with our thoughts." - Buddha
    “When fate hands you a lemon, make lemonade.” - Dale Carnegie

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    Re: Should I install a flow meter to my new install?

    Thanks H2O. This is how I came about thinking I need a flow gauge. I was having trouble deciding which size pump to get, so I figured the flow gauge would help me narrow it down. Sure, it would be after the fact, but hey, better late than never.

    As of now, I'm going to run a 1.5 hp 2-speed pump on this setup (8000gallon above ground). Something kept telling me it was still too much.

    Time will tell. thanks again. I'll read up on that link.
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    Re: Should I install a flow meter to my new install?

    A flow gauge would be a complete overkill for a domestic backyard pool - if you have $400 to blow, spend it on lights or something else
    with a pool this size plumbed in 50mm PVC

    most domestic pools will run around 40' head, a 3/4hp(1.5bhp) pump delivering 80gpm at 40' head will be more the sufficient @ 4800gph or 1.6hour turn over
    now bring in low speed your pump flows drops to 40gpm, pressure drops to 20' - so you will still get 2 turns per day through the filter

    a 27 - 32" sandfilter will be a great match

    bigger pump is not necessarily better

    your filter will come with a pressure gauge that will give you and indication of when it needs to be backwashed

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    H2O_Keeper's Avatar
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    Re: Should I install a flow meter to my new install?

    For a great start BEFORE you buy your pump see this link:

    http://www.poolplaza.com/pool-pump-sizing-2.shtml

    The pump you have in mind does sound a little large. See my signature, I have done the vacuum gauge and pressure test with my manufacturers curve and I get a turn every 8hrs (46GPM). I only have 1.5" tubing.

    Oversizing a pump allows a lot more complete pool water turnovers per day (a turnover is pumping the number of gallons you have in your pool through your filtration system). The rule of thumb is 2-3 per day. Leaning towards three allows some extra capacity should you want to clear up the aftermath from an algae issue or some other problem quicker.

    The only real negative of going too large is that you have exceeded the ideal curve of your manufacturers design. Even if the math works out to where you run your pump a a few hours a day for one turn and you setup timers accordingly you have still used more energy per month. Your pump is working harder than what it is optimized for.

    The above link is kinda a cliff notes version of the excellent pool school article.
    21K Gal, IG, Vinyl, Bleach-Borax-Baking Soda, 3/4HP Hayward pump, Hayward sand filter, 200,000BTU Heater, TF100 Testkit
    "All that we are arises with our thoughts." - Buddha
    “When fate hands you a lemon, make lemonade.” - Dale Carnegie

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    Re: Should I install a flow meter to my new install?

    Thank you to both.

    I did already purchase the filtration system, as well as the rest of the pool stuff. I was deciding over the past 2-3 weeks and received help from people here. I am thankful for that.

    My filter will be a cartridge type. 200sf with the 2 speed 1.5hp pump. I could not get a 1hp 2-sp, so I opted for the 1.5 and kept the 2-speed option, instead of going to 1hp and single speed. Looks like low power will be the way to go most of the time. We shall see.

    After everything is hooked up and running, I will know more on the decision that I've made. I just wanted to make sure I was set before I plumbed everything, so I don't have to go bavck and do things twice.

    btw, I will be using the pool pilot total control system on the pool. So I also wanted to make sure there is enough run time to have the SWG do it's job. Turnovers matter, but I believe the swg needs time to work. A smaller pump would allow the time for that. Everything seems to correlate to one another. I'm hoping low speed on the (uprated) 1.5 2-sp will do the trick. thanks!
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    Re: Should I install a flow meter to my new install?

    "The Blue & White 300 series flow meters are inexpensive and of reasonable quality..."


    The 2" PVC model has a low limit of 40. That may be too high of a starting number for my needs. The 1.5" has a 20 on the lowest reading, but I don't think I want to go down to 1.5 " just to place that on there.

    Although.... I am adapting the pipe up from 1.5 - 2", because the pool comes equipped with 1.5" fittings. Maybe I can place the flow meter directly before the adapter to 2".

    After reading a bunch of the links, I see that even uopgrading to 2" is a bit overkill. I just wanted to do it right the first time, but it seems I'm going overboard. Too much "planning" and not enough 'enjoying'. ha.

    Maybe if it calls for it, I may change the pump out in the future to a 3/4 or even 1/2 hp and run it more often. This is why I wanted the gauges. As it is, the pump that came with the pool was not too much of an extra cost, so it wouldn't have been wise to not get it. I'll see how it works first with this setup before I go changing out anything.
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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    JasonLion's Avatar
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    Re: Should I install a flow meter to my new install?

    The 2" pipe version of the flow meter is also available in a 15-70 GPM version, which is appropriate for smaller pumps (and many mid-sized ones as well).

    I would never call upgrading to 2" pipe overkill.
    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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    Re: Should I install a flow meter to my new install?

    Great! Thanks JL. I didn't see that option when looking. I'm going to assume I want that exact range and purchase that one.

    and... First time someone told me it wasn't "overkill" after I decided something. haha.
    18' x 54" Round AG 7500 gallon w/small prefab 2-piece fandeck
    Waterways 200sf Cartridge Filter, 1.5 hp 2-speed pump. 2" pvc piping
    Pool Pilot Total Control swg w/acid tank feeder
    Pool Rover Jr., BBB, TF 100 test kit

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