The tank has an “emergency” drain (of sorts). Instead of one siphon, there’s 2.....just at the same height.So if either siphon gets fully or partially plugged, the other can handle the flow.That's how the tank came but I converted it over as I wanted an emergency drain.
I was initially going to just go Herbie setup but modified it to go with a bean animal so I can get more flow than a single 3/4 inch drain can provide.. I ran the return external and use the 3 3/4 inch bulkheads for the drain.
When it’s setup like this, it won’t matter if the box was not sealed at the bottom because when the pump stops, only 1/4” of tank volume can go back to sump at the most.
I’ve been pushing 800gph through this system, that’s 4x which is plenty for a 165g tank, I get about 10 gallons back into my 40g sump which it can easily handle.
What’s confusing me is pipe size.
I have 2-1” overflows.......so 2” of total overflow.
I have 1-3/4” return..........so only 3/4” of return.
You have all three same size at 3/4”.....now that’s weird...
Last edited: