Closed Loop System

[Malign Reefer]

What are the benefits or advantages of having a closed Loop System vs an open loop system?

[ca1ore]

What do you mean by an open loop system?

[skip0211]

Closed loop is a great way to add more flow to a system... if open loop means exiting tank water into your sump and back, closed loop is Not a replacement option for that..

[ReefKeeper64]

The OP Probably means open loop = a traditional system, where all water exits the tank via the overflow, goes to sump and then is returned.

A Closed loop also has a traditional overflow component, along with the closed loop.

A closed loop has the advantage of providing very high alternating flow rates without any visible pumps in the display tank. They are very quiet, at least mine is. Also, no wires to be seen. The drawback is they cost more.

[jccaclimber]

Closed loop is going to be more efficient than open in terms of generating flow. In open loop the pump must fight the head pressure due to gravity in addition to the parasitic loss within the pipes. In a closed system the pump just fights the piping loss. Of course this means your lower sections are at a higher water pressure, so you can't just seal a standard sump to get this benefit.

Compared to circulation pumps you see holes rather than circulation pumps on the inside.

[ca1ore]

Originally Posted by ReefKeeper64

The OP Probably means open loop = a traditional system, where all water exits the tank via the overflow.

Ok, OP just asked the question in an odd way because I'd not view one as a replacement for the other - more complementary. So, if open loop means a traditional overflow to sump and a return pushing against some kind of head pressure, then it's a must have (well almost), though for reasons that have little to do with in tank flow. A closed loop, on the other hand is all about in tank flow - that's what it does. Though relatively unobtrusive, it's largely been supplanted by propeller pumps.

[jccaclimber]

I should add that with a canister filter (more common in freshwater) you can do a HOB closed loop and still hide equipment without a drilled tank.

[Malign Reefer]

Originally Posted by ReefKeeper64

The OP Probably means open loop = a traditional system, where all water exits the tank via the overflow, goes to sump and then is returned.

A Closed loop also has a traditional overflow component, along with the closed loop.

A closed loop has the advantage of providing very high alternating flow rates without any visible pumps in the display tank. They are very quiet, at least mine is. Also, no wires to be seen. The drawback is they cost more.

You mean by "cost" you mean the pumps to to deliver the return water at higher rate of GPH?

-John

[d0ughb0y]

there's a reason why closed loop is not widely used.

I had a closed loop setup for a while then switch to using powerheads.
main issue was I used ocean's motion, which caused a lot of problem and talking to the owner is like talking to a used car salesman.

if you have a choice, I'd say don't do it.

[Malign Reefer]

Originally Posted by d0ughb0y

there's a reason why closed loop is not widely used.

I had a closed loop setup for a while then switch to using powerheads.
main issue was I used ocean's motion, which caused a lot of problem and talking to the owner is like talking to a used car salesman.

if you have a choice, I'd say don't do it.

Is is 100% necessary to create ocean like movement in a tank or can you just point your returns in different direction?

[d0ughb0y]

that's right. you can just point the returns in different direction.
I highly advise against using oceans motions. it is a maintenance nightmare. you have to disassemble it to clean it. And if sand gets into it, it easily messes things up, and replacement parts are not cheap, etc etc.

[Malign Reefer]

Originally Posted by d0ughb0y

that's right. you can just point the returns in different direction.
I highly advise against using oceans motions. it is a maintenance nightmare. you have to disassemble it to clean it. And if sand gets into it, it easily messes things up, and replacement parts are not cheap, etc etc.

Ok cool, thanks d0..

[ca1ore]

Originally Posted by d0ughb0y

I highly advise against using oceans motions. it is a maintenance nightmare. you have to disassemble it to clean it. And if sand gets into it, it easily messes things up, and replacement parts are not cheap, etc etc.

Maybe you just had a bad unit. Mine has worked flawlessly for 3 years.

[marinelife]

I have a closed loop system with an Ecotech L1 pump running it and some grye pumps in the tank

[Malign Reefer]

Originally Posted by marinelife

I have a closed loop system with an Ecotech L1 pump running it and some grye pumps in the tank

what made you go with a closed loop? And do you have any pics of the return system.

[marinelife]

I went closed loop to have less pumps in my tank. I do not have many picture its a long tank so hard to get a really good picture of it.

[Malign Reefer]

What is your estimated return GPH?

[heathlindner25]

Originally Posted by Malign Reefer

What is your estimated return GPH?

Are you sure you still understand the difference between open and close system?
Basically a open system will be exposed to air, and a closed system will not be.

[Malign Reefer]

Originally Posted by heathlindner25

Are you sure you still understand the difference between open and close system?
Basically a open system will be exposed to air, and a closed system will not be.

Yes I under stand the difference! I was asking what GPH would be necessary to achieve a ocean "Like" movement on the return.

[heathlindner25]

It depends on how big your tank is and where you place your returns. As your coral and tank grow, the flow will start to become blocked again.
Basically, buy a nice oversized return pump and put valves on all your returns

[Malign Reefer]

Originally Posted by heathlindner25

It depends on how big your tank is and where you place your returns. As your coral and tank grow, the flow will start to become blocked again.
Basically, buy a nice oversized return pump and put valves on all your returns

That is exactly what I was thinking, might even run 2 in-line in-case of a failure.

Thanks Heath

[heathlindner25]

No problem

[jda]

The advantages here are going to come down to tank size and amount of flow. In small tanks, flow pumps are cheap and reliable, but some don't like the look in the tank. In really big tanks, this is a different story.

Generally speaking, the pump that you use in a closed loop will use less electricity than if you use it at head. I used an Ampmaster that would take around 210 watts as a return and it was about 145 as a CL pump. You want to really move some water. You can use eductors if you have enough velocity to really move some water. You want a large inlet and small outlets so that there is significant velocity.

CL can make your tank look cleaner. You can use locline on the outlets to put the water where you want.

Even if you use something like an Oceans Motion, the flow is still somewhat static - just four static zones. I use a CL in conjunction with a wavebox for maximum surface swiping effect.

Unions and ball valves are your friend.

[ReefKeeper64]

This is my tank back in 2013 when I was building it. In the first video you can see the closed loop in action. In the second video the returns are camouflaged by dry rock and polygem 301 marine safe epoxy. You'll quickly notice that there are no visible pumps or wires to look at and the flow is enough to create a tsunami. In fact, I eventually removed the sand because the Reeflo created so much flow I had to dial it back more than I wanted. More flow is the way to go!

Initial closed loop flow test


Later video with camouflage and view of the closed loop plumbing



Now, another member is absolutely right about Oceans Motions having lousy support. That is a one man shop. When I had to make a call back in 2013, I could not reach anyone for days and I didn't think I would ever get it to work. Eventually I did get some support and haven't had much of an issue with mine since that initial setup (knock on wood).

Still, if my Oceans motions unit were to fail tomorrow, I would not even contact Oceans Motions about it. I'd rip it out and replace it with 2 DC pumps and run them both in alternating fashion on a controller. I could program in all kinds of randomization with that!

If you want a closed loop, you have to have the tank drilled for it. There is no getting around it so take that into consideration. For most, its easier and cheaper to get all the flow you need using pumps, wavemakers, Sea Swirls, etc.

[kuzko]

Originally Posted by ReefKeeper64

In the second video the returns are camouflaged by dry rock and polygem 301 marine safe epoxy.

How many fish/inverts have gone down that return? lol