Durso Question

[BlueAbyss]

There is a gate valve between the lower 'main' drain that allows you to slow the flow... it will take some fiddling to get it to work right, but the basic principle is that head pressure built up in the overflow box by the water sitting above the main drain pipe will equalize the draining of the overflow, maintaining a certain water level above the main drain. The secondary or emergency drain is to alert you that there is an impedance in the flow through the main drain.

What makes a Herbie quiet is the lack of falling water, rather the lack of water mixing with air in a turbulent fashion. No air gets into the main drain pipe, so there is no noise. This system can reduce overflow noise also.

[banditpowdercoat]

I'm draining a Little Giant 4 through a 1" line, approx 800-900GPH, handles the flow just fine. I do not have a screen on the intakes. Them being straight pipes, if a critter gets in there, just open the gate valve and plop, into the sump he goes.

[mark]

The height in the overflow chamber is also set by how high the the primary stub is. Can go from none (just the bulkhead) upwards. Advantage of running the water level in the chamber on the higher side is less waterfall noise into to chamber. The water will back up over the top of the primary a few inches but takes a little playing around, just dry fit the stub into the bulkhead (don't need to glue) so it's easy to remove to cut back if needed.

All standpipe can be straight. Don't know what you're planning on flowing but know my 2" drains with Dursos can easily handle 1000gph each and from the different calculators expect them to do 2000gph+ each.