Flow Meter. Is it helpful and/or worth it?

rockyboy

Well-known member
Jul 13, 2007
175
I am about to have all of my equipment plumbed at the pad and I was wondering if a flow meter would be worth the investment. Where should it be hooked up? I will have the standard setup with an autopilot SWG, 30" sand filter and no heater. Just interested in what everyone thinks.
 

JasonLion

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May 7, 2007
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A flow meter is a very handy thing to have. They are typically reasonably affordable (under $100), they allow you to fine tune you system more easily than other approaches, and they give you a more accurate read on how dirty the filter is than the pressure rise does. Obviously you don't have to have one, but given the low price it seems well worth it to me.

Most flow meters require a couple of feet of straight pipe. Install one where you have a suitable section of pipe that all of your water will be flowing through and somewhere that will be easy to look at.
 

ktdave

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May 8, 2007
888
Katy, TX
Rockyboy,
I installed a flow meter and found it very useful in fine tuning the efficiency of my pump.

I posted a thread of the installation HERE.

HERE is another thread documenting a flow meter installation.
 

rockyboy

Well-known member
Jul 13, 2007
175
I am curious about selecting the range. I will have a WFDS-26 two speed pump and I will have 1-1/2 in pipes. The range appears to go from 8-30 or 20-100. I will definitely be over 30 at times but am not sure 20 is low enough. Bitten on the behind by small plumbing again?
 

ktdave

LifeTime Supporter
May 8, 2007
888
Katy, TX
Of those two models, you would benefit most from the 20-100 GPM model. Your Whisperflow pump will be turning 1725 RPM on low speed. I know our pumps (and equipment set-ups) are different, but at 1725 RPM my Intelliflo pump is pushing about 33 GPM. I wouldn't think there would be enough difference for you to get the flow meter that only reads 8-30 GPM.
 

repair_guy

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Dec 18, 2007
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Murrieta, CA
Flowmeters are chosen by one criteria only. The pipe size and type. For Blue White, you need the pipe diameter and PVC or copper. The range on the meter is based on that sizing.
 

duraleigh

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Apr 1, 2007
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repair_guy said:
Flowmeters are chosen by one criteria only. The pipe size and type. For Blue White, you need the pipe diameter and PVC or copper. The range on the meter is based on that sizing.
This topic has not been covered before and probably many folks are interested. I cannot get a grip on this explanation. Repair_guy, can you add a little more info?
 

JasonLion

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You need a different model flow meter for each pipe diameter, pipe orientation (vertical or horizontal), and pipe material (typically PVC or copper). Nearly every pool uses PVC plumbing, so we can ignore the material and for vertical vs. horizontal the meter model must match the pipe orientation but otherwise makes little difference. For most pipe diameters Blue and While, a popular manufacturer, makes two different meters that cover slightly different flow rate ranges. The available flow rate ranges depend on the pipe diameter. You can see a list of the available models in the Blue and White 300 series here.

It happens that the low range meter for 2" pipe covers 15 to 70 GPM, which is nearly ideal for many pools. With high flow rate pools (typically with a spa or large waterfall) you will need to use the high range meter which is 40-150 GPM, which limits how well you can measure low flow rates. For 1 1/2" pipe you can pick either 9-30 or 20-100. 9-30 isn't a great choice for almost any pool as flow rates tend to exceed 30 GPM, so you want to go with the high range model, 20-100 GPM, which will usually be fine but limits measurements on the low end a little.