# Thread: Measure Gallons per minute?

1. ## Measure Gallons per minute?

New Hayward variable speed pump and would like to measure the GPM of my system at various rpm's. Anyone know of a way to do this?

2. ## Re: Measure Gallons per minute?

You'll need to know what your filter PSI is and your electrical usage (power) as well as a few other details about your system. Then you can enter them into this spreadsheet calculator that mas985 created -

OR

If you happen to like plumbing work, you can add a FloVis flowmeter to your equipment pad and get an actual measurement.

3. ## Re: Measure Gallons per minute?

I like the idea of the Flovis meter. Got online and looked at installation videos. My issue maybe finding a long enough stretch of pipe (needs about 13-15" with unions). The only one that is close is the pipe coming out of the pump and going into the filter canister, it's about 13 1-2". I wonder though if this is a good place for the meter. I would think that it would be better to have it after the filter. I would think the water flow coming out of the filter would be lower, more accurate.

4. ## Measure Gallons per minute?

= volume of water coming out of pool
=Volume of water going into pump
=volume of water coming out of pump
=volume of water going into filter
=volume of water coming out of filter
=Volume of water going into pool
They are all the same since you don't have leaks in your system
Granted velocity is different and pressure is different

For all practical purposes it doesn't matter long as you meet the requirements for installation, mounted horizontally with a certain inlet and discharge distances of straight pipe

5. ## Re: Measure Gallons per minute?

Originally Posted by Teald024
= volume of water coming out of pool
=Volume of water going into pump
=volume of water coming out of pump
=volume of water going into filter
=volume of water coming out of filter
=Volume of water going into pool
They are all the same since you don't have leaks in your system
Granted velocity is different and pressure is different

For all practical purposes it doesn't matter long as you meet the requirements for installation, mounted horizontally with a certain inlet and discharge distances of straight pipe
Thanks for the schooling on that. Not my strong suit!

6. ## Re: Measure Gallons per minute?

I also found flowmeters by Blue-White and Aquamaster USA. They are somewhat easier to install. Anyone have experience with these?

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