What is a closed loop?

[spiderpig]

I keep seeing comments about closed loop but I can't find an explanation. I assume it's the opposite of an open loop. If only I know what an open loop was...

I suspect an open loop would be a sump/ref, but am not sure. If that's the case then a closed loop would be a I/O on a pump with no filtration. How/why would that be preferred over powerheads for circulation?

Thanks in advance.

 

[james734]

You've right.. A CL is just what you said. Basically pump water from the tank back into the tank to great flow with going through the sump etc. Why is it preferred over power heads. Most don't just don't like the look of a PH in the tank. Plus it's hard to get the varies flows from a PH. IE: you can take a CL output put a Y in and get flow in 2 different directions. Where with a PH it's single direction.

They both accomplish the same thing just 2 different ways of doing it.

 

[Herefishyfishy]

As with what James said. In an open loop the water flows downhill with gravity into the sump where a pump forces it uphill against gravity back into the tank. Part of the power is just overcoming gravity.The closed loop has no pumping uphill; no head pressure used. The water pressure going up to the tank is the same as falling back down to the pump. The water is drawn out underwater and returned underwater. Means maximum flow relative to power consumption and heat. Requires better plumbing and perfect seals. My open loop cluttered system is noisier and requires a decent sized chiller to compensate for the pumps.

 

[Brenden]

That is easy. A closed loop is what my brain does when my wife is talking.

 

[james734]

That is easy. A closed loop is what my brain does when my wife is talking.

LOL.. It's that also..

 

[mmkeeper]

Heres a link to one..http://www.melevsreef.com/closedloop.html

 

[moortim]

When I am finished with my 55 closed loop the only thing you will see is two drains in the back of the tank and two sea swirl nozzles poking down into the water. That is the main reason I am doing a closed loop, very clean looking with no bulky powerheads taking up space in the tank.

Tim

 

[Krish]

Here are some photos showing a closed loop I once had on my 38gal cube. 2 pumps sucked water directly out of the tank and pumped it right back in making it a closed loop

 

[Brenden]

Only circulation I have on my tank is a 8000GHP closed loop. I also had one on my last tank. I will never have a PH in a display tank. I love it.