Appropriate return pump size

SomethingFishy · Oct 9, 2013

Hey! I am brand new to saltwater though I have years of freshwater experience. One thing that is truly concerning me is the whole concept of having an appropriate pump to fit my tank to return water from my refugium (which I am building from a 29gal) and my 72gal bowfront. I have an overflow built into the tank with an out take hole of about an inch and a half. I had heard everything from 5x my water volume to an 1800gph pump to return. When I mentioned this to my family they gawked and yelled FLOOD! So what exactly size wise should I start with and I know more flow is better but how much can it truly handle? Also the brand choice varies as much as the gph. I am aiming eventually to have this go hard/soft corals while starting fish and live rock.

Thanks for any input!
SomethingFishy

AJsTank · Oct 9, 2013

Check out the DC pumps from Reef Octopus. There are also several other brands out there as well. They are pretty inexpensive, you can adjust the GPH, they produce little heat, they are quiet and most of them you can run external or internal.

787will · Oct 9, 2013

i recommend between 3-5x system volume. reason being the higher the flow through the sump the more bubbles you are likely to create which will be returned to the DT tank, also if you are running a skimmer you want the skimmer to process all the water that goes through the sump, so make sure your skimmer is rated higher than the flow your expecting.
are your refugium and sump combined or separate? imho you want pretty low flow through a refugium so that everything doesn't get flushed out. to give you an idea i have my sump and fuge separate, sump runs about 5x system volume and the fuge about half that. even if you cant have separate tanks for the sump and fuge you can still achieve this method by dividing your sump into 3, skimmer section, return pump in the middle and then fuge. you would then divide your drain line into 2, 1 for the skimmer end the other to the fuge end, you would be able to control the flow into the fuge end with a valve.
also keep in mind when sizing your return pump the head loss!

SomethingFishy · Oct 9, 2013

I currently have the refugium and sump as one in the same. I was trying to decide whether to have the skimmer in the first compartment before the carbon or last compartment with the return pump, or have it hang off the back of the tank. I was also going to use a Marineland C360 for extra filtration/water space off the back, if it was necessary. The extra flow through the refugium makes sense, or else you would have a lot of live sand etc ending up in the last compartment to grind through the pump as well. Would the fuge have enough water flow as the last compartment after the return pump?

AZDesertRat · Oct 9, 2013

Here is a very good article on Sumps and Returns that should answer a lot of your questions.
Melevsreef.com | Acrylic Sumps & Refugiums

You will want your skimmer in the overflow or other early section of your sump so it catches organics and debris as it comes from the display and allows time using baffles to reduce or remove the remaining microbubbles. I also suggest 3-5x the display volume after headloss for your return but lean towards the 5x end.

SomethingFishy · Oct 10, 2013

That makes a lot sense, awesome, thanks guys. Now I just have to wait for the mail to deliver all the components so I can get her started up. Assembling the refugium today to give it time to dry.

Palting · Oct 10, 2013

Nothing is absolutely right nor absolutely wrong in this hobby. Just t give you a range of opinions, here's mine.

So long as you control noise and bubbles, the ideal flow through your sump is about 5X-10X the DT volume. This will present more water volume to your skimmer, your reactors, heaters, and whatever else you have in your sump. A more efficient system. In my case, I have 1400 gph running through my sump, with a 150 gallon DT in a 200 gallon system. For your 72 gallon DT with 29 gallon sump, I would recommend 500-700GPH effective return. Accounting for head loss, you would be looking at a 750GPH return pump.

As to refugium flow, again I subscribe to the theory that you get more efficiency by presenting a larger volume of water over a unit of time. I have a 20 gallon dedicated remote refugium fed by a 600GPH pump. That's a flow that's 30X the refugium volume, presenting a large volume of water over time to be processed by the macroalage and the rocks and substrate that are in there. If your sand substrate is getting blown out of the refugium, then you are either using the wrong substrate or you have your flows set up wrong.

Using the above principles, the mixed reef tank has been thriving for over 3 years, with no microbubbles, no algae problems.

Happy reefing!!

Damon · Oct 10, 2013

Palting said:
Nothing is absolutely right nor absolutely wrong in this hobby. Just t give you a range of opinions, here's mine.

So long as you control noise and bubbles, the ideal flow through your sump is about 5X-10X the DT volume. This will present more water volume to your skimmer, your reactors, heaters, and whatever else you have in your sump. A more efficient system. In my case, I have 1400 gph running through my sump, with a 150 gallon DT in a 200 gallon system. For your 72 gallon DT with 29 gallon sump, I would recommend 500-700GPH effective return. Accounting for head loss, you would be looking at a 750GPH return pump.

As to refugium flow, again I subscribe to the theory that you get more efficiency by presenting a larger volume of water over a unit of time. I have a 20 gallon dedicated remote refugium fed by a 600GPH pump. That's a flow that's 30X the refugium volume, presenting a large volume of water over time to be processed by the macroalage and the rocks and substrate that are in there. If your sand substrate is getting blown out of the refugium, then you are either using the wrong substrate or you have your flows set up wrong.

Using the above principles, the mixed reef tank has been thriving for over 3 years, with no microbubbles, no algae problems.

Happy reefing!!

Same theory I recently changed my system to with a DC return pump(speedwave 10K) and it's been a noticeable improvement over the lower rate over the 10x sump volume I was previously running. Add to that, that my electricity consumption had dropped massively changing to a DC pump.

It's funny because I pull more good skim and the corals are growing much better than I had even thought. My pH also is on average 0.04 higher than it was at the lower flow. I went from approximately 630gph to 1200gph after head loss on my 110 DT(140 gal TSV). I also have a manifold running my media reactor from the return.

And the nice thing is I can always dial it back if I really wished to.

Sent from Note 2 on Tap Pro

udsmkh · Oct 11, 2013

I am just starting also and I bought a Mag Drive 12 for my 120 and I have to throttle it back to about 25% because my 1 1/4" drain can not keep up with the pump's flow rate. It may be because it has a single drain and a single return, I don't know. I wish I would have bought a lower flow pump and not have this one throttled back so far where I am adding heat and wasting electricity. I have two Hydors running to keep my water movement up.