Return Pump Sizing Help.

[daveydoodle]

It's my understanding that sump tank turnover should be considerably less than DT turnover. To accomplish this, it sounds like most people use more Powerheads / Wavepumps, etc. in the DT to create greater turnover or movement.

Knowing that I'll utilize something such as a Koralia Powerhead, or similar product to increase gph movement in the DT only, I'm having a hard time sizing my return pump.

I'm working on a mixed reef tank, 75 gallons. 1.5" and 1" drain and return respectively. Single overflow, with a dual (split) return. Approximately 4" max head height, two (2) elbows in the return AFTER a "T" with a gate valve directing water to the refugium.

I seem to be between trying to maximize the output of a Mag Drive 7 or throttling back a Mag Drive 9.5. I can use several gate valves on the return to throttle it back, but then that places unnecessary strain on the pump itself.

Any suggestions or experiences? I've used a few calculator modules to determine what my gph would be after imputing the head height, return pipe diameter, number of elbows, valves, etc. but was hoping for live feedback or experiences.

What would you guys suggest as the DT turnover vs. sump turnover? Any other variables you need to know?

Thanks for the help.

 

[Luisra]

I have a 75g tank too, and my return pump is a Gen-X PCX-20. It has worked like a charm for many months. I also have an MP-40 for tank circulation. I personally don't like Mag Drives, too hot for an aquarium pump. Hope that helps!

Info on Gen-X PCX-20 (pressure pump)
Flow rate: 634 gph
Max head: 9.8 feet
Connections: 1" Hose Barb Inlet/ 1" Hose Barb Outlet
For external use only

 

[daveydoodle]

Luisra,
I've never had a GenX pump, however I've had great results with the Danner Mag Drives. I've used their 24, 18 and 12 on different fresh water in sump, submersible set ups. I've never used an external pump, but certainly it would be cooler just based on the fact that it doesn't effect water temp as much by the dispersion of heat from the motor.
At the gph that you have on yours, do you get enough turnover and flow in the DT as well as the sump? How is yours set up; number of elbows, valves, head height, etc? Do you feel like you have "ample" gph to work with in your plumbing?

Thanks

 

[AZDesertRat]

Running a Mag pump internal or extrenal makes no difference as far as heat gain, the motor is product cooled meaning it has internal water jackets or passages the tank water flows through and acts as a heat exchanger.

That being said, Mag would be one of my last choices. They run hotter than comparable pumps, can be very noisy, tend to have vibration problems with time and are not very enery efficient.

For about the same money an Eheim or Ocean Runner is a much better choice based on some bench testing I did using all three brands of pumps plus others I would not recommend such as Quiet One, Via Aqua and Rio Hyperflo.

In my testing I used a 10 psi pressure gauge and valves to calculate head, a 1" flow meter and graduated containers to measure flows and a Kill A Watt meter to measure power consumptions. I also ran the pumps in closed ontainers and used a lab grade digital thermometer to measure heat gain.

The Ocean Runner 3500 and 2500 came out just slightly better than the Eheim 1262 and 1260 but almost too close to call but the others trailed by quite a bit and some just plain failed.

This was several years ago and I wish pumps like the Red Devil and Water Blaster were out at that time, I would love to get my hands on a Water Blaster, I think it may replace my OR 3500's one day.

I would always go slightly larger than you anticipate needing and install a ball valve on the discharge side to throttle flows. This actually makes pumps more efficient and does not harm them in any way, a centrifugal pump only works as hard as it has to plus a little for efficiency losses. Its not and easy one to grasp but it has to do with something called the "Laws of Affinity" and with "Bernoulis Law", but can be pretty dry reading.

I keep my return pump in the 5x display tank range to minimize velocity through the sump and so the skimmer works better and I reduce the possibility of carrying microbubbles back to the display, even with 3 baffles it can happen. I have a 100G display and a 30G long sump with an OR3500 and supplement that with two Koralia Evolutions 1400's on a Reefkeeper Lite wavemaker function set at 30 second switching intervals. The OR3500 also returns to the tank via a 1" return line split in two via a Oceans Motions Squirt two way so get lots of random flows.

 

[Luisra]

Luisra,
I've never had a GenX pump, however I've had great results with the Danner Mag Drives. I've used their 24, 18 and 12 on different fresh water in sump, submersible set ups. I've never used an external pump, but certainly it would be cooler just based on the fact that it doesn't effect water temp as much by the dispersion of heat from the motor.
At the gph that you have on yours, do you get enough turnover and flow in the DT as well as the sump? How is yours set up; number of elbows, valves, head height, etc? Do you feel like you have "ample" gph to work with in your plumbing?Thanks

I know they are great pumps, but I consider them to be a pump & heater at the same time. I don't run a chiller, only an air conditioner so I prefer to use external pumps. I do get a LOT of turnover in my tank due to the Vortech pump, either way I had to remove one of the flow accelerators (3/4") cause it was too much flow and couldn't keep any LPS. I do have a video of my set up before adding any corals, check your PM.

@AZDesertRat Great info!