Calculating volumetric flow for discharge line

reefgirl189 · #1 03-12-2012, 06:30 PM

I'm looking for a formula for calculating my discharge flow rate from my return pump which will allow me to factor in the total head loss. I'm not concerned with the flow loss over the elbows and such but it would be nice to be able to factor in those as well. Which is the best one to use?

patman · #2 03-12-2012, 06:36 PM

There is a calculator of head loss on reefcentral.com

sphelps · #3 03-12-2012, 06:37 PM

Quote:

Originally Posted by patman

There is a calculator of head loss on reefcentral.com

http://www.reefcentral.com/index.php...oss-calculator

reefgirl189 · #4 03-12-2012, 06:51 PM

I know... my return pump is not an option unfortunately...

I have to do the math the good 'ol fashioned way!

Aquattro · #5 03-12-2012, 06:54 PM

How accurate do you want to be? The math can get ugly. Friction coefficients of pipe, laminar vs. turbulent flow, pipe diameters, restrictions in fittings, etc

sphelps · #6 03-12-2012, 06:54 PM

Quote:

Originally Posted by reefgirl189

I know... my return pump is not an option unfortunately...

I have to do the math the good 'ol fashioned way!

What pump do you have?

reefgirl189 · #7 03-12-2012, 07:27 PM

Quote:

Originally Posted by Aquattro

How accurate do you want to be? The math can get ugly. Friction coefficients of pipe, laminar vs. turbulent flow, pipe diameters, restrictions in fittings, etc

Friction coefficient of PVC is 150?
specific gravity is 1.025 for SW

Go ahead and get ugly with me. I enjoy a challenge!

I'd like to be within +/- 250 gph for accuracy, but I'm not going to lose sleep over a mistake. I just like to know what's going on with my system.

What I want to do is install an orifice plate or turbine flowmeter but that would be a bit extreme

reefgirl189 · #8 03-12-2012, 07:30 PM

Quote:

Originally Posted by sphelps

What pump do you have?

Sedra 20000

I can't find a comparable pump for 2000 gph at 0 head on reefcental's chart. Most of them are little pumps. The Iwakis are sort of comparable but I don't recognize the models that are on the list. Plus my Sedra's internal and the Iwakis are external, which kind of plays into the math a bit.

sphelps · #9 03-12-2012, 07:34 PM

Quote:

Originally Posted by reefgirl189

Sedra 20000

I can't find a comparable pump for 2000 gph at 0 head on reefcental's chart. Most of them are little pumps. The Iwakis are sort of comparable but I don't recognize the models that are on the list. Plus my Sedra's internal and the Iwakis are external, which kind of plays into the math a bit.

Just use the Mag 18 or 24, it's the same basic design. Fill in all the info and use the generated head pressure on the flow chart for the Sedra to get flow rate.

reefgirl189 · #10 03-12-2012, 07:38 PM

Quote:

Originally Posted by sphelps

Just use the Mag 18 or 24, it's the same basic design. Fill in all the info and use the generated head pressure on the flow chart for the Sedra to get flow rate.

Yeah that's true. It has a bit less ability for head pressure but it's pretty close. Thanks!

700 gph ish.

Good enough!