A closed loop draws water from well below the surface of the tank. And feeds a pump that returns the water to the tank. It's closed so no air can get in. Hopefuly someone can do better than me.
A closed loop is a circulation system that has a pump that draws water directly from the main tank and then pumps it back into the main tank. It is generally used instead of powerheads and many times in addition to the overflow/sump/return pump.
A couple of the benefits are:
<ul type="square">[*] No powerheads are visible in the tank[*] Since the line going into the pump is sealed and comes from the main tank, the pump has no head loss due to vertical height. In other words, it does not have to overcome gravity and therefore pumps more water faster than if it were pumping up from a sump.[*] They are easy to make DIY.[*] They will not drain the tank if the pump stops[*] The pump is external so it does not add heat to the water[*] You can plumb the output to sea swirls to create chaotic water movement
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A closed loop draws water from well below the surface of the tank. And feeds a pump that returns the water to the tank. It's closed so no air can get in. Hopefuly someone can do better than me.WW
