Closed loops: time to try it out and need some pointers.

[SeymourDuncan]

Tank: 2x5ft x18 in deep. Roughly 75g

The tank has 2 holes drilled in the back and was originally designed for the return, but they are a few inches from the top and drain the tank during power down. Instead of using a check valve because they are not reliable, I am thinking of drilling a 3rd hole and putting the return in that and making the existing holes a closed loop. It also has a single 1.5inch drain, so I'll be pumping it good.

I have a mag12 on hand, so I would love to put it to use.

Some things I have already considered:
Unions for maintenance
Minimal, if any, 90s
Make the outlet diameter smaller than the inlet.
Should I use hose anywhere as a shock absorber? The glass is .5 inches thick

Pump placement...I could make a padded shelf to minimize noise vibration, I have heard people using a mousepad. The pump has to be concealed though as the stands cab is going to be a dog bed and my sump is in another room. I have about 8-10 inches of space behind my tank.

 

[Reefing Madness]

 

[mfinn]

I'm going to do a closed loop on a new tank build and I plan on using single union valves on each side of the pump. This way I can isolate the valve for service.
I'm using single union valves instead of double union valves because the singles are shorter and I'm cramped for space.

The mag 12 is in addition to a main return pump?

For a closed loop, I would have 1 hole for suction and atleast 2 holes for returns.

 

[SeymourDuncan]

Well I took the hole space up with my return but modified the plumbing in tank so it won't drain anymore. The mag 12 just seemed over the top plus it minimizes the flow I can have on my wave controller....and I found a good deal on 2 jebaos. I'm probably just going to sculpt out a rock to hide them. I am still very interested in doing the closed loop but maybe I will so it on my 90g instead, once I get it empty of course.

So the 90 has one overflow box off center. If I used the mag 12, what would be the best setup for flow but not overkill? The 90 is going from reef to predator and my reef is going in the tank I originally wanted closed loop.

 

[AZDesertRat]

With powerheads/wavemakers getting smaller and smaller and much more energy efficient it is hard to justify a closed loop anymore. I replaced mine with Seios, then Koralias, Then Evolutions and now Jebaos and the power consumption and heat gain are about 1/4 or less what it was with a large pump. And the Jebaos are not much bigger than the Loc Line that was the closed loop returns.

 

[mfinn]

One important thing about using a closed loop, getting those ugly powerheads out of the tank.

While I love my Tunze 6105's and the flow they create with the 7095 controller, they were a distraction along with the cords.
I am trying a closed loop with a Dart/Snapper on my new tank, with hidden loc-line. I don't really like to see much of that either.

I will be hanging on to my Tunzes, just in case.

 

[SeymourDuncan]

That snapper is one heck of a pump. I had one that I never used but tried it out and I could t believe the flow.

 

[mfinn]

Back a few years ago I used a mag9.5 for a closed loop, but the suction side was plumbed over the top.
The return went to a sea-swirl.
Worked pretty good.
I was lucky I had a canopy to hide the pvc that went higher than the rim of the tank.

 

[JSaquatics]

I used the 4 way oceans motions on my 150 closed loop tank and was great

 

[SeymourDuncan]

Good point, I wouldn't want to be crammed and restricted