:bablefishHey i am new to the forum but checked out your listing i have a spare overflow never used willing to let go? let me know if you are still interested. I added a pic if you wanted to check it out.
When I used this overflowbox it never lost it's syphon. What I did when I did a water change was; I left the pumps running until the water level in the tank fell below the intake slats in the overflowbox. Once the water level fell below I then turned off the pumps, and I did the reverse when filling the tank back up. Once the water level reached the slats and began taking in water again I then set the pumps running.
If I recall correctly it was rated to handle 1200gph. It is up in my addict I don't have the measurements. If you are really interested I'll go up there.arg