Originally Posted by tmcpeek
Nitrate--- I did drill a hole in the return fitting inside the overflow, but it did not seem to do anything about siphon. Maybe I drilled in the wrong spot?
The hole doesnt go inside the overflow, it goes on the pump return into the tank. When the pump quits running the water thats is left in the tube running up from your sump to your tank quickly reverses direction and creates a siphon that in turn will drain the tank until the siphon is broke. The hole you drill will be on the return into the tank, and as FF stated it should be 1/16" diameter.
My first SW
tank was a a great learning experience, I flooded my floor several times before I figured out where the water was coming from.