Custom tank pipe sizes

[teacherthomas]

If I am building a 110gallon tank (120x60x55high cm) and getting holes drilled for an internal overflow , is it better to have 2 time 3/4 inch returns and 2 times 1 inch out, or one 1inch return and one 1.5 inch out? How to decide?

[phillyfishguy]

I went with 2 1-1/2 for drain and 2 1 inch for returns..

[Ron Reefman]

I'm setting up a new 55g QT and I'm doing 3ea 1" drains and 2ea 3/4" returns. One drain will run wide open, one will have a durso and one will be a bit above the water surface as an emergency drain. I'm doing all the holes in one end and setting up with a shadow box behind the back glass (just for fun). I'd do it with my 180G DT but there is WAY too much plumbing already back there. Maybe when I redo it in 10 years!

[teacherthomas]

Originally Posted by phillyfishguy

I went with 2 1-1/2 for drain and 2 1 inch for returns..

What kind off low is that for?

Would one 1.5" and one 1.0" out and the 1.0" for return be ok? What amount offlow would that handle? I am assuming that the overflow should be 0.5" bigger than the return to handle the flow and possible a 1" backup. Correct?

[Ron Reefman]

If you can, I'd say do two 1.5" drains and one 1" return. The drains feed by gravity and that sets a fixed rate of flow. One for use and one for emergency. The 1" return has flow established by a pump and can move as much or more water than a 1.5" gravity drain. That's why you'll want a ball or gate valve in the return line after the pump, to control the return flow rate.

[teacherthomas]

Originally Posted by Ron Reefman

If you can, I'd say do two 1.5" drains and one 1" return. The drains feed by gravity and that sets a fixed rate of flow. One for use and one for emergency. The 1" return has flow established by a pump and can move as much or more water than a 1.5" gravity drain. That's why you'll want a ball or gate valve in the return line after the pump, to control the return flow rate.

THanks for the info.