Ball Valve? Closed Loop on Sump? Flooding problem?

[banzai75x]

Okay I'm pretty stupid, so please don't kill me.

I'm getting ready to start my first tank and I want to do it right the first time so I have some questions.

What's a ball valve do?

I have an internal overflow (1") that runs down to a sump. I'm planning on getting a pump and returning the water through one pre-drilled hole on the other corner of the tank. Is this considered a closed loop?

Q: What happens if the pump shuts off? I know that the sump should handle enough water for the overflow, but what about the pump return. Since that is in the water as well, won't that create a siphon and drain the tank into the sump?

Closed Loop: Having a pre-drilled hole for water that drains to a pump and then running the pump return back into another pre-drilled hole. Since water is always in the system, it is a closed loop right? Closed loops may/may not have a sump in between?

What recommedations would you have for me for my 60 gal? I already have 1 hole for the overflow, and one for a return next to the overflow.

I'm planning on drilling another hole somewhere and split the return from the sump into the two returns.

Should I drill two more holes and make another closed loop?

[MalHavoc]

A closed loop is a loop that has no "breaks" in it, or is otherwise not exposed to the atmosphere. An example of a closed loop would be if you had two one inch holes drilled in the back of your tank, well below the water level. One hold was connected to PVC that went directly into a pump intake, and the pump output was connected directly back to the other hole with PVC. There is no "break" or sump or anything involved. Because this system is closed, there is no draining or flooding that can occur if you turn the pump off.

A ball valve is just a valve that you insert at strategic places in your plumbing, so you can turn off water flow if you need to disassemble your plumbing. For instance, you might put one between your sump and your return pump, and then one immediately after the pump and before your PVC so you can turn both valves closed and remove the pump for cleaning without water spilling everywhere.

In your situation, if the power went off, water would drain back down through the line until the water level dropped below the hole in the tank - not something you want to have happen. It will empty a large portion of your tank.

Unless you're willing to make a third hole in the tank and set up a real closed loop, I wouldn't use the single hole in the tank all by itself.

I'd probably do this:

use your overflow to drain water into the sump. Have your return pump send water back up over the side of your tank, and empty out into the tank, sort of like how a power head would work.

I'd drill another hole in the tank and then set up a real closed loop with a second pump.