overflow question

[GaryLCrouch]

I was thinking of building a acrylic overflow. Anyway to attach the overflow to the tank while it is up and running?

[shecter]

Waterweld would probably work. It wouldn't look pretty though.

[ca1ore]

Is there a hole drilled in the tank already for the overflow you are thinking about making? If there is a hole in the back of the tank near the top, then post-fitting an acrylic overflow box is easy. Otherwise not so easy.

[GaryLCrouch]

The tank is already drilled. I have a 90 pointed up with a screen on the top. But it is not skimming the top and pulling water from below leaving a film on the top so I wanted to add the overflow to control the water flow and also to get better skimming off the top of the water.

[ca1ore]

Easy then. Build a 5 sided acrylic box (not 4 sides) out of 1/4 inch. Drill a hole in one of the sides for a bulkhead that aligns with the hole in your tank. Drain the tank down to below the hole. Remove your 90 degree elbow and the bulkhead. Reinsert the bulkhead with the flange/gasket on the outside back of the tank. Slip the overflow box over the protruding part of the bulkhead inside the tank and thread the nut back on. No silicone needed.

[GaryLCrouch]

Ok so I have a mag 5 pump in my tank. My question is what gph overflow box should I buy. I figured some water is used going into the refugium and some into the skimmer. So should I get like a 700gph or.....?

Setup:

I have a 1inch drain line leading to my sump. the water goes through the skimmer and to my return pump in the middle chamber. The return line goes up and tees off, one side to change water ( closed )and the other side goes to a refugium which pours water over the baffle back to the middle chamber which of course puts some water back to the refugium and the rest back to the DT. Hope that made sense lol. I actually right now leave me pump wide over and controle the flow with how much water goes through the refugium. The less flow through the fuge the more water drains quicker in the pump chamber and the more flow through the fuge the more water fills up.

[ca1ore]

Are you going to buy an overflow box or make one? I personally don't like the ones available to buy because they are only four sided and require you to silicone them to the back of the tank, which means leaving it partially drained for 2 -3 days.

[GaryLCrouch]

I might just build one. I have a 3 sided one I never used for 600 gph so I guess i could just use that and put a back onto that one so I would have to make one from scratch