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What size return pump for 90 gal mixed-reef?

16003 Views 8 Replies 4 Participants Last post by  usmc121581
I'm starting a 90 gal mixed-reef system and I was wondering what the recommended gph for the return should be. I have a MegaFlow overflow box with a max flow-rate rating of 600gph (according to the All-Glass website). My LFS recommended a Mag-Drive 18 return pump which provides 900gph at the return nozzles (9' rise). The overflow box appears to be able to handle the flow but the drain is noisier than I would like.

I also currently have 1 Maxi-Jet 1200 powerhead pushing 295gph.

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The Mag 18 is probably at the limit of the 5-10 times total tank volume rule. Is it internal or external? If you put it in the sump that thing runs hot. I believe they use around 200w of electricity to run. Think of how hot a 100w light bulb is, then think of where that heat is going. In your tank. I would have recommended an Eheim to cut that wattage in half. If your sump is acrylic talk to somebody about drilling the side and externally mounting the pump. It'll work just the same except the heat will not transfer to the tank.

You have probably got about 900GPH in the tank itself. About 10 times the total volume. You should try and get it up around 2,500GPH or more for a nice reef. To stagnant of water grows weak corals and allows algae to run free. Your lfs recommended that Mag18 as your sole source of circulation, they do that all the time. They don't like to sticker shock folks. Just kind of ease them in. Then when things go wrong and you are in for $2,000 already, sure you'll pay another $100 to correct it.

What type of PVC piping came with the overflow of your tank? Do a search for "durso standpipe" online. They will silence your overflow noise you are reffering to.
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I have the Mag 18 in the sump and as of yet have no heat problems (we'll see when I fire up the lights), thanks for the tip though -- I may consider going with an Eheim in the future.

As for the GPH I'm a little confused (forgive me I'm new at this!). If I understand you correctly, the Mag 18 putting out 900GPH at the tank is actually on the high end of the 5-10 times total tank volume rule and I could get away with a lower GPH (say 500GPH) if need be as long as I provide enough supplemental circulation (to achieve 2,500GPH) in the tank with powerheads?

BTW, the MegaFlow kit that came with my tank has what appears to be a Durso style stand pipe. Check it out here:
i had an 18 and now have a 12 and neither really ever got warm in the sump. My lighting will heat my water 14 degrees in 6 hours if it is not fanned though.
You will never feel the pump get "hot" in place, the water moves it all around the tank. All motors get hot, there is no arguing that. It's a matter of finding the most efficient one. T you have the basic idea that you don't need your sump whizzing by, and that more flow in the tank is a better idea. You can create a closed loop system if you prefer not to look at extra power heads. Extra power heads add heat as well. Therefore it is essential to find ones that work the best, that being Tunze Turbelle as they have models that can move 1,600GPH on 11 Watts of energy.
you know cafe i really never thought about it, but for an engineer that was pretty dumb of me, i revoke my previous statement. so if you take it out of the sump it wont heat the water really at all than?
Correct Andre and both Eheim and Mags can be ran external. You just need a hole in the side of the sump that matches up to the pump. A correct bulkhead and you are off and running. Most of the folks I know will install a street ell into the bulkhead pointed down. What's that you say? What is a street ell? A PVC 90 that has a male thread on one side and a smooth slip fitting on the other. The goal is to screw it into a bulkhead, point it down so that about 1/4"-1/2" space is between it and the bottom of the sump. Why? So you never have to worry about your sump level running dry. You can get by with an inch of water in your sump if need be.
lol, the things i would never in a million years think of.
You will always learn something new in this hobby no matter how long you have been doing it.
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