Corner Overflow Box Design

[goldfish69]

Hi Forum.

I bought a 90g tank with a left corner overflow box (sitting inside the tank) with 2 pipes (one drain + one return) drilled at bottom of tank. A friend of mine says that the drain/return pipes are too close to each other and that they should be at opposite ends of the tank to have good water exchange.

Is he correct?

Also, how large should each pipe be? 1"?

Thanks

[Ron Reefman]

You can direct the return flow out away from the overflow box with some loclline pipe and nozzles so the fact that they are on the same side isn't a big deal. Doing it his way would require 2 overflow boxes (1 at each end) which is marginally better, but costs more to produce and now you have 2 overflow boxes to look at.

One pipe should be bigger than the other. The drain is the bigger one and the return is the smaller one. They should be like 3/4" & 1" or 1" & 1.5". You want to drain more than you return. And the drain only runs on gravity but your return will have a pump that can push higher pressure than gravity can.

[mjm7757]

If you are really concerned about putting them on different ends you can always run your return at the opposite end and then use the smaller hole in the overlow as an emergency overflow.