Closed Loop Systems?

[rdnelson]

Hey Guys:

I have seen mention of closed loop systems and have a general idea of what that is but..... I would love to have a detailed explanation of what they are, how they work and the pros and cons. Someday I hope to be able to upgrade to my dream tank and would love to learn what options are available when that time comes.

As always, thanks for all the advice and info.

Rich

 

[dakota9]

Following along, as I think that's what I designed in my 30 cube, but not certain of the terminology.

If it's what I have, then it's a perfect design!

 

[grouper therapy]

In aquariums any system that draws the water from the same source it supplies without interruption is a closed loop. Power heads are technically a closed loop. The return pump located in a sump is not a closed loop since it pulls water from one container and pumps it to another with a interruption in the loop , the overflow.

 

[rdnelson]

Ok, so that isn't at all what I was thinking. LOL But, it makes perfect sense now that I read it. So, I have seen several build threads where it appears the returns are coming up through the bottom of the tank. Seems that would be a nice way to get get flow where you would like it and circulate through the live rock better. Is there more to it than that?

Getting back to the closed loop, your explanation would leave me to believe that the only purpose of the closed loop is for flow since no other form of filtration is provided (unless a canister type is inserted in the closed loop). Is that correct? Would (and how would) a skimmer be incorporated into this type set up.

 

[grouper therapy]

rdnelson99;710770 wrote: Ok, so that isn't at all what I was thinking. LOL But, it makes perfect sense now that I read it. So, I have seen several build threads where it appears the returns are coming up through the bottom of the tank. Seems that would be a nice way to get get flow where you would like it and circulate through the live rock better. Is there more to it than that?

Getting back to the closed loop, your explanation would leave me to believe that the only purpose of the closed loop is for flow since no other form of filtration is provided (unless a canister type is inserted in the closed loop). Is that correct? Would (and how would) a skimmer be incorporated into this type set up.

A closed loop is for circulation only in lieu of power heads.There is no vertical head loss in a closed loop only static head loss from the friction and fittings in the plumbing (very little).
Pros: Typically inexpensive compared to some power heads. Aesthetically pleasing by providing an opportunity to hide outlets within the rock work or substrate. Multi directional. Can be serviced without removal from the display tank. Completely silent when remotely located away from the display tank. Can also be used in conjunction with rotating devices. Really not a pro or con but can be installed with or without additional bulkheads.
Cons: Higher operating cost per GPH moved. More expensive to control varying flow rates, but can be done with a VFD. More work and skill required to initially install. I'm sure there are other cons but I am biased so others will add to the list

 

[rdnelson]

So, in a typical closed loop system the only filtration would be the LR and LS correct? Because it is a closed loop, there is no concern related to siphoning back to the sump or overflow of the tank because there is no reservoir other than the tank and the plumbing correct?

This setup would also not allow you a place to grow macro algae and or include a skimmer either unless I am missing something or you go with a HOB skimmer and/or fuge correct?

grouper therapy;710777 wrote: A closed loop is for circulation only in lieu of power heads.There is no vertical head loss in a closed loop only static head loss from the friction and fittings in the plumbing (very little).
Pros: Typically inexpensive compared to some power heads. Aesthetically pleasing by providing an opportunity to hide outlets within the rock work or substrate. Multi directional. Can be serviced without removal from the display tank. Completely silent when remotely located away from the display tank. Can also be used in conjunction with rotating devices. Really not a pro or con but can be installed with or without additional bulkheads.
Cons: Higher operating cost per GPH moved. More expensive to control varying flow rates, but can be done with a VFD. More work and skill required to initially install. I'm sure there are other cons but I am biased so others will add to the list

 

[rdnelson]

10-4 Gotchya.

 

[grouper therapy]

bratliff;710824 wrote: NO.

A closed loop is generally installed IN ADDITION TO a regular overflow, with sump, refugium, etc. So, you'll have an overflow into a sump, with a return pump, skimmer, etc., i.e. all the stuff you would expect for filtration (really anything you want) AND you'll have a separate system with its own dedicated pump that just provides water movement.

Exactly. It is for water movement not filtration.:up:

 

[patrick]

The best closed loop design will tend to take water from areas that have lower flow and are fairly deep in the aquarium and put that water near the surface where the only gas exchange occurs........and in doing that they greatly aid in your biological filtration. Nitrobacter and nitrosommomas only do their thing if well oxygenated.