Overflow/return line plumbing 180 gallon

Hello,

I've been a freshwater aquarium keeper for years, however, I'm new to saltwater/reef. I'm setting up a 180 gallon acrylic tank that I've had in the basement for about 10 years and I have a couple of questions.

First, this tank has never had water in it, so it's not drilled yet. It has two box overflows, one in each rear corner, but only one of them has the slots in the top for water to drain. My question is do I try to cut slots in the other one, or put two drain pipes in the one that already has the slots in it and then just bring the return lines up the one that doesn't have the slots?

I'll be running two external pumps for the return that push about 1,000gph at a 3' head. I'm unsure of whether to drill the back of tank and return the water that way or to bring both lines up the solid overflow box and come through that.

Please give me your suggestions.

Thanks

 

Welcome to 3 reef Leroy

can you get any images up of what your dealing with here

it sounds to me that one side is the overflow, and the other side is for the return

or it may have been built to act as a back up overflow, thus has no teeth and only operates if the overflow with the teeth gets blocked up, water level rises and then this overflow comes into play, preventing a tank overflow

Steve

 

Yeah, I'll try to get a pic of it tomorrow. The side with no teeth goes all way up to the top of the tank.

If I did use one side for the overflow and one side for the return, what should I do with each of the 1" return lines? Just 90 degree turn them out through the overflow box and into the tank, or make some kind of spray bar from each one?