Sump/Fuge Question

[coraline79]

I have an unusual situation. I have a 55 gallon tank converted to a sump, and it is all tempered glass. I have a iwaki 70 external pump that I want to use with this. The partitions in the sump are made of plate glass so they can be drilled. I was wondering if I could plumb a bulkhead near the bottom of the plate glass on the return side to create a constant siphon. here is a poor drawing to give you an idea.

[hobogato]

you could, but why do you need a bulkhead? if you ran hard plumbing up and over into the return chamber, it would do the same thing and you wouldnt have to go thru the baffle. you will have difficulty starting the pump because of air in the line, and there is a risk that it will not restart after a power outage if it is run this way (up and over the side of the sump)

[coraline79]

That is what I was trying to prevent. If I have it plmbed through the baffle near the bottom, the weight of the water would keep it primed, where as if I have a pipe up and over it will lose prime right? There will be aproximately 15 gallons of water and the tubing will be 3/4 or 1 inch.

[hobogato]

whether you have a pipe that just runs over the side and ends close to the bottom, or a pipe that goes over and ends close to the bottom thru a baffle, the physics is the same. the water will not push itself over the side of the tank simply because there is more water above the end of the pipe. you will have to manually start the siphon over the side to get to the pump and if that siphon is broken during a power outage for some reason, the pump will not be able to start it again.

[coraline79]

Ok, I was just hoping this might resolve it. I think I am just going to have to deal with the siphon until I get a better idea.