ATO issue.... maybe

[Mandosh]

Originally Posted by paddyob

The res is tall.

angles down into the sump.

You have to make sure the output of the top-off hose is higher than the water level you run in the reservoir or you're going to get gravity feed.

EDIT:

^^ what he said...

[cale262]

I have a tall res for one of my tanks, much higher than the level in my sump so I ran the top off line to the DT overflow which is higher than both.