Herbie Help

[The Guy]

Originally Posted by reefwars

That would be my first guess too , an ato is a must as the water level in the return has to be stable.

I never run my Hebrie with a trickle down the drain.

Filter socks , water levels in the return pump are the usual causes of fluctuations.

Filter socks are good as long as there kept clean otherwise I think there a PITA. I run an ATO using the double float system into the return pump area, which gives me constant level accuracy for the pump.
I use filter floss in my bubble trap area just before the return pump chamber for cleaning and don't use socks anymore, and always trickle down the emergency overflow, It works well for me. I just maintain a clean Herbie strainer in the overflow box.