refugium for 75 gallon

[singlejm]

I'm am considering adding a refugium to my 75 gallon reef tank. Plumbing is a serious weakness for me in this hobby so i need some advice. I need to know how big of an overflow I should get since my tank isn't pre-drilled. I am considering using a 29 gallon for my refugium but don't know how much GPH the overflow should be rated at to accomadate a 29 gallon. I am looking at CPR continious siphon overflows. They make a 600 and 800 GPH. My main question is if i get the 600 how big does the return pump need to be? I'm assuming 600 at least but can, or is it benificial to go with a larger return pump cause you would have to account for the rise of the water from the refugium back to the tank. I was going to use a mag drive as a return pump.

 

[Len]

You might want to consider a hang-on refugium if you want to keep it simple. But if you want a larger one below the tank, look for a small overflow that will handle about 300-500gph. CPR has ones in this size: CS50 should do great, but get the CS90 (600gph) if you really want more flow. You don't need much flow through refugiums, so a small overflow box is fine.

Get a pump that is properly sized for your overflow. You will need to take into account the height of the pump along with some loss due to bends and friction. For the CS50 at 5' of head, a Mag 5 is ideal. For a CS-90, a Mag 7. You can always put a ball valve on either (or both) return and overflow plumbing to restrict either flow, but it is best to get the two relatively close to start with.