agsansoo

Here's my HOB overflow box and sump.

The overflow box is a weir type, the other type of HOB overflow box is called a U-tube type.The powerhead to the right of the box is used to pull air out of the overflow. Without this, the overflow could will loose it's siphon.



Here's the back of the box.



Then down into the sump.

Peterpiper

oK so any air that gets trapped in the high point gets pulled out by the power head and if no air is present the power head ( air line ) would just be pulling a little water. that smart!
How loud is this set up? does it make a sound like a sink?
Thanks for the post, some times a picture is worth 1000 words

agsansoo

Mine is silent. I'm only using a Rio 1700 return pump .. so about 350gph @ 4 feet. Any thing over 400gph, gurgling !

Scooby_too

Does your return from your sump connect to the Power head. Also is that the air line to remove air from the overflow.

agsansoo

No the returning water goes straight back into the tank. And yes, the air line removes air from the overflow box. Because the pump is sucking the air and water out through the air line.