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Aquarium Advice Activist
Aug 29, 2006
Virginia Beach, VA
OK - I have been reading up a bit and I am planning a 55gallon in the next few months. Something I dont understand is this.

If you have your tank draining into a sump and then have a pump pushing the water back up to the tank what happens when the pump turns off. What makes the tank STOP draining?
In the main tank you have some sort of overflow.

As the water level rises in the main tank from the the water being pumped from the sump below, it spills over into the overflow in the main tank.

that water then flows down through a tube back into the sump.

as soon as the pump in the sump/fuge stops working (gets unplugged, jammed, fails or whatever) then the water stops going into the main tank, the water level in the main tank stops rising, and water stops overflowing.
You would drill a little hole in the PVC that drains from the tank in order to break the siphon. This hole should be a little under the water level, but not too low that the sump doesn't overflow.
If it's a reef-ready (pre-drilled) tank then the overflow is set at the water line. The return(s) should then be set just below the water line. Water will backflow through the return line (from the pump to the tank) until the siphon is broken. You need to test the placement to be sure that you have enouhg excess room in the sump to handle the overflow when the pump is shut off. Most sumps are less than half full when running.
A little lesson learned hear with the return lines is to have a hole drilled below the water line and one above. I've had my sump overflow because of a blocked hole in a return. More then one will keep that from happening!
Is there a diagram anywhere that shows how this all comes together? I guess I dont know what a Reef Ready tank looks like. How does it differ from a regular tank?

Sorry for all the stupid questions. I am really curious how this stuff works. Its very interesting to me...
Reef ready means it is already drilled for a sump/fuge. They tend to me more expensive. A non-drilled (or non-reef ready) is your standard tank.
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