I have a 46 gallon with holes drilled in the back. i used flexable pvc 3/4" return and 1" drain. i have both lines running up above waterlevel on the outside of the back of the aquarium. i thought this would help the reverse syphen if power failed. it seems as if it still returns syphen threw the pump if i unplug the pump. then i read you have to drill a hole in the return line just below water level. how can i do this with no overflow box. i have the tank with the holes drilled in the back with bulk heads. the only thing i could think of is inside the tank run some pvc back up and then down again and drill a hole in that. is there any better way. also am i going to have the same reverse syphen effect on the drain line if the pump fails. will it continue to drain into the sump threw that line also if i dont do something about it. please help..
