External overflow drain size

[Stang67]

I will be getting a 180g tank that will have a synergy shadow external overflow. The 3 drain pipes are 1.5 inches. I will be running a basement sump and need to get the pipe size down to be able to fit all 3 between the floor joists. What is the smallest I can reduce them down to? 2 returns are 3/4 inch with a vertical lift (head pressure) 8-9 ft.

 

[sunken3]

i would keep them as large as you can.. the gravity vs pump power just doesnt compare. that said, put some valves on your 3/4" return, that way whatever you downsize your drain to, you can slow you pump to match.

 

[DCR]

With only 3/4" returns, 1 inch drains will be plenty. Could even make the full siphon a 3/4", but I would prefer a 1". I would leave the other two overflows at 1".

 

[Stang67]

I am thinking of getting a DC return pump so I think that may help with the return flow adjusting as well. If I can get the drains down to 1 inch that would be perfect for all 3.

 

[RobB'z Reef]

just curious, any reason you went so small with your return lines on a tank that size?

 

[Stang67]

That's what the builder recommended I am going to double check the specs now just to be sure.