What is a closed loop?

Thanks,
Cpt Sumpless

A closed loop is a means of creating current by using an external pump. So your input(s) of the pump and the output(s) of the pump are in the same body of water, hence it is a "closed" loop (as opposed to something like a sump return, which is "lifting" water and hence "not" a closed loop).

HTH :smile:

Thanks. I assume the advantage would be keeping powerheads, etc from taking up space within the tank.
Sorry for piggybacking on the thread.
Cpt

Well I hate to say it but after three or four really bone head moves I now hate my planed overflow/return system. I should have listened to you all. So I'm going to build a simple return and the side holes are going to be converted into a closed loop. It's going to rain all week end anyway. I wonder if I'll ever get livestock in it ;)

Jason

Why would you not put a T in the return line outside the tank with a riser to above the water level. Then put a breather valve on the riser. These are basically check valves that allow air into the pipe but no water out. They are designed to be siphon breaks in drain systems.

so it basically looks like this:

Riser & breather valve
|
|--- To bulkhead
|
from pump