what is a closed loop?!?!? so......confusing(for me:p)

[The Reefer91]

some one explain to me the concept of the closed loop. do you need to drill the tank to do it? will any pump do? could i also see some pics?

i haven't been able to get a clear discription.

 

[EdwardMinor]

Go to melev's reef web page. He shows it with pictures and the tank he used is not drilled.

 

[LOTUS50GOD]

a closed loop requires that the inlet and the outlet of the pump be plumbed into the tank.....

 

[SDguy]

A closed loop does the same thing as, say, tunze streams. Provides circulation. Except the pump is external, not in the tank. It's a closed loop because it is simply water exiting the tank, through a pump, and back into the tank. An "open" loop would be like your sump. Water exits the tank, but to a sump open to the air, then gets pumped back. When the pump shuts off, the lines drain of water. On a classic closed loop, when the pump shuts off, the lines remain filled with water.

hth

 

[The Reefer91]

thanks for the replies, i was confused at first, but it seems so simple

 

[dougchambers]

It's very simple. In it's simplest form we created a closed loop for our 75g using a MAG7 sitting on top of our overflow feeding a Seaswirl. Worked great.

Our new system is a little more complex, but the principle is still the same.

They are great for consistent amounts of water flow without adding pumps and heat inside the display.

-Doug

 

[RxReef]

So why do you need a closed loop system? what about just putting another powerhead in?

 

[cfarrow2]

So the sump is separate from the closed loop? Not sure I see the point. I see the point of good water flow, but why separate it from the sump system? It would pick up a lot of oxygen, etc. before getting pumped back into the display.

 

[cfarrow2]

I've been seeing the term "bulkhead" a lot lately, does that just simply mean it's a hole in the bottom of the tank, rather than in the back or side of it? Are these questions that we should be asking in the DIY forum, or in the Newbie forum?

 

[Ewan]

<a href=showthread.php?s=&postid=6845299#post6845299 target=_blank>Originally posted</a> by cfarrow2
So the sump is separate from the closed loop? Not sure I see the point. I see the point of good water flow, but why separate it from the sump system? It would pick up a lot of oxygen, etc. before getting pumped back into the display.

If it were just another pump pumping from an open sump, the pump would have to overcome the head loss from the sump to the tank (assuming the sump is below the tank). A closed loop does not encounter this head loss, so you're getting more flow from the pump. ie: A pump may produce 600gph at 0' of head, and only 300gph at 4' of head. Friction losses from the pipe still apply.

Additionally, folks like myself have no need for 1500gph blasting through their sumps. Salt spray and microbubbles are the result, despite many, many efforts to avoid both. I have recently switched return pumps to a small Pan world pump, and have my larger pump placed in a closed loop configuration. the result is more flow in the tank, and no microbubbles.

Here's a great thread that addresses the large return pump issue:

http://www.reefcentral.com/forums/showthread.php?threadid=550482&highlight=why+return+pump

-E.

 

[SDguy]

<a href=showthread.php?s=&postid=6845299#post6845299 target=_blank>Originally posted</a> by cfarrow2
So the sump is separate from the closed loop? Not sure I see the point. I see the point of good water flow, but why separate it from the sump system? It would pick up a lot of oxygen, etc. before getting pumped back into the display.

You really don't want that much turnover going through your sump. Noise, microbubbles are just a few of the problems you would encounter. For example, I'm using a sequence hammerhead on a CL for my new 115g, and only about 600gph for the sump return. There is no way I could use a hammerhead if it was all running through the sump.

A bulhead is the fitting you attach to a hole in the tank, regardless of where it is. Just look up "bulkhead" at aquatic ecosystems or marine depot for pics and description.

RxReef - for me, aesthetics. I didn't want any pumps in the tank, so I opted for a closed loop. You could just use PH, or if you have the bucks, tunze streams. My tank is only 18" deep, so I'd be hard pressed to hide these in my tank.

hth

 

[dougchambers]

<a href=showthread.php?s=&postid=6845260#post6845260 target=_blank>Originally posted</a> by RxReef
So why do you need a closed loop system? what about just putting another powerhead in?

You can do another powerhead, but they add heat, require regular maintenance, and are more prone to failure. There's also the ugly issue of additional cords hanging in the tank.

So the sump is separate from the closed loop? Not sure I see the point. I see the point of good water flow, but why separate it from the sump system? It would pick up a lot of oxygen, etc. before getting pumped back into the display.

The sump is completely independent of a closed loop. The benefit is that they allow for more flow without pushing more water through your overflow and sump which is prone to developing microbubbles. They do not pick up a lot of oxygen, etc before getting pumped back into the system. The water is pulled from the display through the pump and right back into the display. You can also use water diverters (squids, OM 4-Ways, Seaswirls, etc.) to randomize the flow better.

I've been seeing the term "bulkhead" a lot lately, does that just simply mean it's a hole in the bottom of the tank, rather than in the back or side of it? Are these questions that we should be asking in the DIY forum, or in the Newbie forum?

A bulkhead is simply a pass-thru to adapt to a hole.

Bulkheads typically come with threads or slip(glue) inserts to allow various types of plumbing to be attached. Bulkheads can be pretty much anywhere you can put a hole and seat the flange.

-Doug

 

[SDguy]

<a href=showthread.php?s=&postid=6846587#post6846587 target=_blank>Originally posted</a> by dougchambers
The water is pulled from the display through the pump and right back into the display. You can also use water diverters (squids, OM 4-Ways, Seaswirls, etc.) to randomize the flow better.

[/B]

Or have it return through a manifold. Multiple changable directional outlets.