refugium and sumps

[GregJ]

I'm probably going to feel stupid once someone anwsers this for me, well here I go. My question is about how they work, flow wise. If you have an outtake going from your tank down to your sump, at which point you would have a pump connected to another hose going back up to the tank intake,how would you control the amount that is being pump up. If the pump is to fast, then won't their be to much water being pumped up to the tank, or do you just make a really big outtake hole? I wanted to try and make one using something like a small submersible pump or powerhead.

Thanks,Greg

[Doug]

Hi Greg,
The tank needs an overflow to feed the sump. The return pump then feeds water back to the tank and it goes into the overflow at the same rate, returning to the sump. So the amount leaving the tank, cant exceed the amount being pumped into a tank.

Make sure the return is just at water level, so back siphoning is minimal when pump is off and make sure sump is large enough to handle any back flow.

[Troy F]

If your return pump exceeds the rate of your overflow's flow into the sump you can put a ball valve on the return line and adjust as neccessary.

[BCOrchidGuy]

Frankly thats a good question, depending on what return pump you are using it may come with a flow control or you may have to go to a ball valve.

My sump has a pump for my main tank and a seperate very small pump for my refugium, I aimed for 80 gallons/hour through my refugium which is a 45 gallon tank.

You want to circulate your tank volume around 10 times per hour or more, your refugium should have a flow of 1-2 times its volume per hour.

If you use a small submersible pump or power head try to keep your sump/refugium above the tank, if your sump is below the tank just go for gravity feed. There are lots of overflows that will fit on an undrilled tank available just phone around to some of the LFS to get an idea of prices. Ultimately a drilled tank is the best way to go, but I use two overflows and they work fine, I think they are ugly though.

Remember to set the overflow box so if the power goes out the sump won't overflow, my returns from my sump have small vent holes so the water isn't siphoned back into the sump through the pump.

[GregJ]

Thanks guys, glad to hear it isn't that stupid of a question. My next question was going to be whether I couldcget around drilling my tank. It's only going to be a 7 minibow, and I'm kind of worried about drilling it. I know lots of people have , and I've only heard of one person who actually cracked the glass, but I'm still nervous doing it. Let me know what you think.

Thanks,Greg

[BC_Grl]

You could probably use an external overflow instead of drilling the tank. We have an external one and I hate it!!!!! If I had any other choice, it would be -hands down- drilled. It is easier to control the return pump, and you don't have to be worried about them overflowing. And if the power goes out and comes back on, what will re-siphon it? There are just too many "ifs" if you don't.

[GregJ]

Does anyone know of a good place to take a tank to get drilled? Were would I get the bulkheads(I think thats what they're called) to put around the hole?

[Troy F]

Big Al's is good. A 7gal might be tricky. I know there was no gaurantee on my 15gal I had drilled but it turned out fine.

An internal overflow box would take up too much space in such a small tank.

Out of curiousity Greg, is this your first go at a marine set up?

[GregJ]

It sure is I have a little experience with saltwater from working at big Al's, but nothing to do with reefs. Oh and I keep freshwater stingrays and discus

[Bob I]

In my considered opinion I would not worry about refugia or sumps on a minibow. Some of us use Aquaclear Mini's on those little tanks. Come and visit in the nanoreef section where there have been threads about those little tanks in the last week.