Critique my plans for in-tank flow

[jelazar]

I'm working on a 350 gal display tank and I'm having second thoughts about how to provide enough in-tank flow. The tank is 96x28x30 (LxDxH) and I'd like to have a lot of flow.

The tank is just a couple feet from our dining room table, so it needs to be as quiet as possible. I mean, really quiet. Most of the equipment is in the basement to keep things, you know, quiet.

So my plan has been to use two Vectra L1 pumps in the existing holes for two closed loops. (The tank had large corner overflows when I bought it.) A 2" intake on the back wall feeds the pump. The Vectra discharges water through a short manifold then out from loc-line nozzles along the front of the tank. In-tank plumbing will buried under the sand. Nozzles will be camouflaged with rocks and corals.

That was the plan. But while this all looked good on paper, it doesn't look as good in person. In order to hide the plumbing, I'll need a 4" sand bed. That's more than I like. What's more, that will take up a lot of the viewable space and make the view too letterbox.

Also, the loc-line nozzles will be more visible than I imagined. Either I have four evenly-spaced blobs of rock to hide them, or there's a bunch of black nozzles contrasting against my white sand bed.

Finally, I'm underwhelmed by the Vectra L1. My pumps are sorta quiet up to about 50% power, but get noticeably louder after that. I upsized the plumbing and used the larger couplings. Flow isn't bad, but I'm not impressed.


What do other big tank owners do? How did you get lots of flow across an 8' tank, silently, with minimal eyesore? Move the loc-line to the top front of the tank? Go with some other in-tank powerhead? My experience with MP10s is that even the quiet drive isn't silent. I've read many reviews that the same is true for the gyres. Get more of them and run them slower?

 

[Sacohen]

I had a similar design on my 120 many years ago.
I had a perforated pipe (kind of like a spray bar) sitting just on top of the sand.
I hide it by placing it in the middle of the tank and building the base of the rock work around it.
The thought was to keep water moving inside the rocks.

One issue that you may not have condidered is that with the plumbing that low in the tank if you lose power that will become a drain and all of your tank water will drain down to just below the tops of the loc-lines.

I had a electric ball valve (solenoid) that would snap shut (in a millisecond) if I lost power to prevent the back flow of water out of the tank.

 

[pdxmonkeyboy]

subbed.. I am currently designing a closed loop for my 200DD

 

[jelazar]

I had a similar design on my 120 many years ago.
One issue that you may not have condidered is that with the plumbing that low in the tank if you lose power that will become a drain and all of your tank water will drain down to just below the tops of the loc-lines.

You may not see it in the picture, but the closed loop pump draws water from a bulkhead halfway up the rear tank wall. So even when the pump is off, nothing drains.

 

[jelazar]

We've been thinking about this a lot, and our new plan is to run the closed loop plumbing along the top eurobracing. I think the nozzles will be much less noticeable, and will allow me to move/change/reconfigure the nozzles more easily. Plus the sandbed will now be an uninterrupted expanse. We won't get quite as much uplift on any settled detritus, but I still think this will be a better form/function balance.

I expect I'll need to supplement the closed loop Vectras with some sort of in-tank powerheads on the back wall at some point. My thought for now is something very large (MP-60/Gyre 280) at low to medium power, rather than a normal-sized pump (MP-40/Gyre 250) at high power. That will cost more, but may be quieter. The side walls are prime viewing panes, so I won't put anything on the sides unless it's a last resort. So for now I'll keep collecting peoples' reports on sound levels and pump output.

 

[jelazar]

So here's what the new closed loop plumbing looks like. We're much, much happier with how the nozzles blend into the black background now.

The new design also makes it easier to adjust the direction of the nozzles. I can also make changes to the plumbing if I need to, without draining the tank and pulling out all the rock.

We also picked up a pair of Gyre 280 pumps to experiment with. I'd like to place them on the rear wall of the tank so they're out of sight. Maybe mount them vertically pointing in opposite directions, and alternate flow. Or point them both in the same direction and let 'em rip!