Closed loop

[Duane Fagan]

So I have to ask probably a stupid question but hey why not....... So I was thinking, using a ecotech L2 pump in in closed loop mode would be possible if the inlet was in the sump..... The idea came up while thinking about how people with 2" thick acrylic aquariums get flow

 

[Ron Reefman]

I'm not sure I'm reading your idea properly. You want to add a pump, take water from the sump and pump it... where? Into the display tank?

In a closed loop the intake and output of the pump both need to be in the main tank. Otherwise it's just another return pump.

 

[Duane Fagan]

I'm not sure I'm reading your idea properly. You want to add a pump, take water from the sump and pump it... where? Into the display tank?

In a closed loop the intake and output of the pump both need to be in the main tank. Otherwise it's just another return pump.

Yeah basically but the L2 has closed loop option with different flow modes. Would it be possible or good idea to use closed loop mode from the sump to the display

 

[albano]

.... The idea came up while thinking about how people with 2" thick acrylic aquariums get flow

Who do you know with 2” thick acrylic tanks?

 

[TheGreatWave]

Try it out and see, you might be able to use the reef crest or lagoon but not gyre. (Gyre reverses flow)

I use a Adam's hybrid closed loop that also works as the return pump, but it's a big all in one tank. I guess in theory this would work in your tank as well.

 

[Ron Reefman]

If you have a skimmer in the sump and/or an auto top off system, the variations in the amount of water that gets pumped out of the sump/refugium could be a problem. It all depends on where the shimmer and ATO control are located relative to the pump.

The pump has the variable flow rates so that if it were in a real closed loop system it could vary the flow. As just a return pump it could be a problem and it is NOT a closed loop.

 

[TheGreatWave]

If I could add to the ATO problem. In my tank the water level doesn't fluctuate, but it would in a different setup.

As it turns out this isn't really a problem as the ATO would still have the opportunity to top off the tank whenever that chamber is lowest (when pump is at highest flow) The rest of the time the ATO sensor may be submerged.

I figure as long as the ATO gets a few opprotunities throughout the day to top off the tank, that is sufficient.

 

[Jeff_H]

By definition this setup would not be a closed-loop design, but I assume you're talking about the Ecotech mode called closed-loop. That said - I see no reason why it wouldn't work as long as your plumbing from the overflow is large enough to support the GPH you will need to get the flow you want from the pump. Keep in mind you will have head pressure when not in a true closed-loop design so your max GPH will need to be calculated from the max 3100GPH rating.

Personally, I used the L1 in a closed loop and while it worked, I eventually took it down since I didn't see the benefit of enough extra flow I wanted from the setup. One advantage you should see (that I didn't) from using it as an extra return pump vs a closed-loop is the lack of debris (think sand) getting into the pump and causing noise. I even had the return line mounted high in the tank to reduce this issue, but I was always having to mess with it to clear sand out of it... Very annoying! With the inlet in the sump, you will not have this issue.

One other thing to consider is how silent your overflow is. If you have your overflow tuned to be quite, you will likely have a hard time keeping it silent since the pump will be constantly changing the amount of GPH over the overflow. A true closed-loop will not do this since the water doesn't go over the overflow.

Final thoughts... With 2" acrylic I assuming the tank is huge. Do you want the closed-loop to have a cleaner look, or are you OK with cables in the tank? When I compare a powerhead (or wavebox) to the L2, I can achieve the same amount of flow with fewer watts. depending on placement, I would consider building mounts that would work with powerheads for the walls of the tank or hide the powerheads in the rockwork if you can hide the cables (see below). Just my .02 cents from using a closed-loop in the past.


Tunze Stream rock

Stream Rock - Tunze

Hi-Tech für Aquaristik

www.tunze.com

 

[WVNed]

You could run the pump that way. Your sump level would fluctuate since the drains would probably be constant. You could design around that too but it would be more trouble than benefit.

 

[TheGreatWave]

@Jeff_H brings up a good point about overflows, if you want to use a bean animal style that could be an issue, unless, you drastically oversize the plumbing, particularly the second drain so that it could accommodate a much wider fluctuation in water flow.

 

[BestMomEver]

We had a 500 gallon acrylic tank years ago with a closed loop. We drilled 1” holes in the back wall. We then built a pvc rack to mount our rock to (we had LOTS of rock) and drilled 100’s of little holes all in it. The pvc that formed the rack ran up the back of the tank and through the holes and ran to the sump where it was connected to a pump (additional to the return pump). The pump sent water from the sump through the pipe where it came shooting out all the holes. There was rarely any detritus in the rock work and the flow it created was insane. I wish we could do it again but the tanks we’ve had since have been too small.