This is when I picked it up.
Sent from my iPhone using Tapatalk
So the overflow on these tanks are call Herbie (drain). There are two pipes, the one with the valve is your primary and the other is an emergency drain (edrain).
Your primary drain is where all your water goes, no water is supposed to go down the edrain except... well you guessed it in emergencies.
If you hear sucking you should close the primary drain valve till it stops making small moves. You are basically covering the pipe with water and making it into a full siphon. [The Red Sea’s have a weird silencer on this pipe. In the pic above it’s the larger pipe to the right.]
It takes some practice and in both the Red Sea, WaterBox tanks it’s hard to tell when you are in the edrain. Just use small moves on the valve and listen closely.
BTW there is no level adjustment in these tanks, the water should never get below the btm of the overflow teeth. Not sure what’s goin with the level in that pic.
Hope that helps!
Sent from my iPhone using Tapatalk on