I think I need more "umph" in my return line...


Reefing newb
I thought I would be OK, but let me run some numbers to you tech geeks out there.

I have a 65g DT with a 24g sump.
Return plumbing is 3/4".
There is a T in the return line to a valve controlled feed line to the fuge (low flow).
The main tank return line is split to two outputs in the tank (standard AGA setup for corner overflows).
The return is approximately 6' tall.

I am using a MAG-5 return pump and I'm getting some "OK" current, but nothing to write home about.

I'm not concerned with flow in the tank as I have a Vortech MP-40 turned about 50-60%.
I am just concerned about turnover....

Any thoughts? Should I be at a a MAG-7 or MAG-9.5 with the head loss and T-s I have?

Thanks in advance!
Your tank overflows should have a gph rating .. get the closest pump to that and hook it up to a ball valve. The head loss should drop the return to slower than the max overflow drain and then you can dial it down a bit with the ball valve if its too fast and gurgles
IDK what the rating would be on a standard AGA corner overflow tank. 2 1/2" bulkheads.
I also have to take into consideration the Y valve from the return pump to the fuge.
400 gph i think if it the single corner overflow... or 800 gph if it is a double. You will probably get some nasty gurgling if you go for 800 on the nose so maybe aim a bit lower.

If say you aim for 700 gph total the mag 7 is not going to cut it due to head loss unless you are getting a couple hundred gph from your fuge return... even then i think it would be more convenient to spend the extra 20 bucks and get the pump rated for 950 gph and use a ball valve to dial it down.

You do not have quite enough information listed to do the exact math but http://www.reefcentral.com/calc/hlc2.php is a good head loss calculator.
I'd rather have a slower flow through my sump than a 10X turnover rate.That way my skimmer has more time and can remove more waste from the water.
I'm only running a Mag 9.5 on my tank going to both returns.The pump on my skimmer ( mag 12 ) is bigger than my return pump.
The AGA overflow are listed at 600gph max. but realistically it closer to 450gph max.

A Mag 5 would be about perfect if it wasn't split going to the fuge.I don't see a problem going with a 9.5 since it is doing double duty,fuge and display return.
this dosent have overflow info but here is a chart by chompers from MFK as far as plumbing that helped me when i built my tank

Cross Sectional Area (in square inches) - Pipe sizes vs. their cross sectional area. Useful for dividing flow between pipes.
size __area
1/2 = .1963
3/4 = .4418
1.0 = .7854
1.25= 1.227
1.5 = 1.767
2.0 = 3.142

Maximum Gravitational Vertical Flow - This is what we look for when sizing drains or DIY overflows. The flow under the power of gravity reaches a maximum in the same way an object reaches Terminal Velocity as it falls through the air. The gravitational force is countered by the waters viscosity (resistance to flow) and the frictional resistance of the pipe. The viscosity creates a minimum vertical length to acheive the maximum flow. If the vertical pipe length is less than the minimum, the flow rate will be somewhat less than the pipes maximum potential.
size _GPM __GPH
1/2 = 2.50 = 150
3/4 = 5.63 = 337.5
1.0 = 10.0 = 600
1.25=15.6 = 937.5
1.5 = 22.5 = 1350
2.0 = 40.0 = 2400

Min. Vertical Length
1/2 = 2"
3/4 = 5"
1.0 = 9"
1.25= 14"
1.5 = 20"
2.0 = 36"

Frictional Head Loss per 90 (measured in Feet of Head)
size_ head loss
1/2 = .00970
3/4 = .00220
1.0 = .00386
1.25= .00602
1.5 = .00878
2.0 = .00156

Anyway... Each measurement is at the pipes maximum flow rate in the Vertical Flow Rate chart. When calculating the loss for the pump side, these values are slightly more.

There is a very conservative rule when estimating head loss. It is one foot of head per fitting. This rule does not take into account flow rates, pressure, actual frictional losses, etc. It does not have to because it is too conservative. If you multiply any of the above head losses by one thousand fittings, you will be very surprised at the actual head loss. (hint: just move the decimal to the right three places.)

Gravitational Horizontal Flow This is for horizontal applications that do not rely on a pump, or the force of a vertical pipe. These flow rates are considerably less than the vertical rates because gravity does not offer a significant horizontal force. It is a balance of gravity and the viscosity vs. the cross sectional area of the pipe.
size_ GPM
1/2 = 1.563
3/4 = 3.517
1.0 = 6.253
1.25= 9.769
1.5 = 14.07
2.0 = 25.0

In this application, you would use the chart for Vertical Flow.

In this application, you would use the chart for Horizontal Flow.


What ever happened to "I just want to watch a couple fish swim around in a tank?"

:) Thanks for the information...very helpful.