[marcom50]

I have found a few sources on calculating water flow rates for pumps in aquaria. But I was wondering if there are any affordable devices that can measure gals/hr, and where can it be purchased???

[organicreefer]

no ,i reeaaly doubt such a product exists
the only thing i can think of is fill a container of a known quantity and timing it ,then doing the math??

[Ltspd]

Originally posted by marcom50
I have found a few sources on calculating water flow rates for pumps in aquaria. But I was wondering if there are any affordable devices that can measure gals/hr, and where can it be purchased???

Affordable, No.

Devices, yes. Dwyer makes meters and such that can measure gph or what ever. Most of these are large and costly.

http://www.dwyer-inst.com/htdocs/flow.html

[Rin]

They're called rotometers. Basically a ball in a graduated tube. Flow goes through the tube and elevates the ball to the given flow rate. Very reliable and accurate enough for aquaria. You can probably get a really good one for under $100.

Downside they will add a little to the frictional losses. And they must be installed on a vertical leg of hard pipe to measure accurately. The ones made from plastic aren't as accurate, but I think that plus or minus 5 gallons/hour isn't really an issue here.

If you want something digital, then nothing is cheap. Don't bother with hand-held units. There is no way to get a reliable reading with these.

For the those where money is no object, get the coriolis meters. No frictional losses, accurate to within 0.01%. The best ones measure flow by vibration. They're the most accurate you can get. Most models will also measure density, temperature, and total gallons. Some models can also detect reverse flow. Almost all have one or more electronic outputs for computer use. They must be installed in such a way as the pipe (where the measurement is takeing place) is always full. They also tend to be large and require added support to remove stress from the pipe. Cheap coriolis meters start at around 8 big ones. Make sure to specify titanium piping.