hang on overflows with reefs

mwfishkeeper1

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Sep 10, 2007
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I have a glass 100 gal with a sump getting ready to set up and I was wondering if i can use a hang on the back overflow with a reef setup. I was told by my LFS that I couldn't put any corals in there because I dont have sufficient flow. Is this true? If not, what types of corals could I put in? Thanks all!
 
Yes, a hang on the back overflow box can be used with a reef tank. If the tank is not drilled, there's really no other way to move water from the main tank to the sump safely. The pump that goes in the sump will need to be properly sized in order to prevent flooding -- too big and the overflow won't be able to drain water fast enough; too small and air bubbles become more likely to form in the siphon tube of the overflow box, which can break the siphon. Fortunately, the range between too small and too big is pretty large, so it tends to not be a problem as long as one knows what they are buying when choosing a pump to pair with an overflow box.

Otherwise, in general, flow within the tank can be increased with one or more powerheads. I've always like the Maxi-Jet powerheads, but I just got a couple Hydor Korilla powerheads to try out. Typically, it's not desirable to have the majority of the flow in a reef tank to be the result of circulation from the main tank to the sump, but that can vary depending on what the goals of the tank are. Ultimately, most reef tanks have more than one powerhead on top of any circulation created by flow in to / out of a sump.

What type of corals do you want to keep? Different corals have different flow requirements as well as lighting requirements. How much flow do you currently have? What type of lighting do you have (bulb type, wattage, number of bulbs)?
 
I don't normaly say things like this ... but your LFS is freaking retarded.

That's the dumest thing i've heard from an LFS in a while.

Not only is he wrong but he's stopping you from buying things.

As far as what FSN77 said .. he's absolutely right ... what I did in my old tank was if the overflow was rated at 600gph I got a pump that was rated a little higher ... and when you lose headpressure because the pump is pushing up and loses power you'll still be ok. Just put a ball valve on the return and the drain and this way you can even compensate with that.
 
Alright, great thanks guys. Btw, yes I have a single Korilla 4 for my 100. Do you think this would be enough or should I get a second? I mainly want to keep a bulb anemone (I know they require a certain amount of flow) so I was wondering if a hang-on would be sufficient as far as flow goes. As for corals, I was thinking about a small variety except for sea fans. Mainly polyps, some mushrooms and soft corals. Thanks.
 
Soft corals are OK with the right amount of light and powerheads. I grew some fantastic corals with an overflow. Just don't try to do hard corals.
 
Great thanks for all of the input! I'm really excited to start growing a reef now. Who knows, maybe you'll be seeing some pics from me soon...
 
I have two 1200g hang on overflows on my 150g reef,I run a Mag 18 with a closed loop system,and it works great.Just make sure to use Aqualifters to keep them siphoning encase of a power failure.
 
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