Closed loop...

[ShawnSaucier]

I’m in the process of looking to start a larger system. One of my issues is flow. On my current 190g I have 4x MP40qd currently. This tank for some reason has been a powerhead black hole. I’ve run Tunze, Gyre, WAV and back to the Vortechs.
I’ll be honest, I’m kinda over all of the wires, customer service calls, ect.
On my new system I am really leaning toward a closed loop. Looking at the display to be 72”(possibly 84”)x 48”x 24”(possibly 30”).
For those that do run or have run a closed loop, how many returns would you have for the dimensions? What are your pros and cons for a closed loop system?

 

[CC13]

I’m in the process of looking to start a larger system. One of my issues is flow. On my current 190g I have 4x MP40qd currently. This tank for some reason has been a powerhead black hole. I’ve run Tunze, Gyre, WAV and back to the Vortechs.
I’ll be honest, I’m kinda over all of the wires, customer service calls, ect.
On my new system I am really leaning toward a closed loop. Looking at the display to be 72”(possibly 84”)x 48”x 24”(possibly 30”).
For those that do run or have run a closed loop, how many returns would you have for the dimensions? What are your pros and cons for a closed loop system?

I get where your coming from. I gave Gyres a try in my system right now, and still am not 100% satisfied. I seem to not be able to hit all the spots I want without either adding more pumps (means more power bars, wires, ect), or ramming up the % the pumps are running but this causes massive flow in other areas that are less than desirable. They also cannot be connected, monitored or have custom flow schdeules controlled by my Neptune which I consider a massive flaw and huge drawback to the pumps - so much so that for this reason alone I would not buy them again.

I too was considering a closed loop system for my current tank and the only real drawback I found was if there is a leak in any of the bottom bulkheads, you pretty much have to tear the tank down. This really was not an option for me and I didn't want to have thousands of dollars invested in a system on what would ultimately reply on a .02 cent rubber bulkhead gasket. There are other ways to run a closed loop, but the ones I considered had the input water drains on the back glass, and then the return lines went up threw the bottom panel of glass. So like I said, if the bottom panel seals or bulkheads start to leak at all in the future, your in a pretty uncomfortable situation.

 

[AlexStinson]

I’m in the process of looking to start a larger system. One of my issues is flow. On my current 190g I have 4x MP40qd currently. This tank for some reason has been a powerhead black hole. I’ve run Tunze, Gyre, WAV and back to the Vortechs.
I’ll be honest, I’m kinda over all of the wires, customer service calls, ect.
On my new system I am really leaning toward a closed loop. Looking at the display to be 72”(possibly 84”)x 48”x 24”(possibly 30”).
For those that do run or have run a closed loop, how many returns would you have for the dimensions? What are your pros and cons for a closed loop system?

I had a 185 (60x30 footprint) it had 2x 1.5" intakes and 4 3/4 returns (one in each bottom corner) plus another 2 over the back powered by a hammerhead pump. Seemed to work pretty good for flow, but I still used a few powerheads for more turbulent flow as I didn't have any fancy gadgets on the closed loop.

I haven't done it again simply to avoid those possible leaks at the bottom of a large tank.

 

[ca1ore]

Have you tried something like the Vortech MP60? I find the MP40 rather underpowered, particularly for a larger tank. Closed loops are fine, I run one on my 450, but they are hardly a panacea. When I do run them, I make sure to plumb them with pump-native pipe and never go through the bottom of the tank; they work just fine through the top of the back.

 

[CC13]

When I do run them, I make sure to plumb them with pump-native pipe

What is pump-native pipe?

 

[jda]

Get a pump with 2" intake... you can just have one intake in y0ur tank, but have a few strainers on hand. I then would use four 3/4" returns with with loc line - maybe 2 in the back and two from the bottom that you can point different ways. With the Loc Line, I could use anywhere from 4 to 16 nozzles. You want a little bit of back pressure or else you lose all of the velocity - people used to fail with CLs with 1" returns where they moved a lot of water, but it barely moved getting into the tank. I tried to use 45s and spa flex more than 90s, but sometimes you cannot avoid it. A good high-flow pump like an Ampmaster, Hammerhead or LifeGuard will not even really blink at a few 90s in a CL.

Also, do not underestimate eductors if you need more flow. You need velocity to run these as well.

Most larger pumps run more efficiently in a CL than they do on a return... I had an Ampmaster 4300 that was about 110w less in a CL situation.

When you decide on which pump to use, look for a good used one for a backup. Be sure and use the split unions that the good pumps come with so that you can swap out pumps in no time. Also, ball valves on the intake and return are a good idea.

FWIW - I have larger tanks too. I have had great luck with Tunze 6100 and 62XX, but I also have started to mix in some EcoDrift 20.X pumps... not too expensive and they move more water than a MP60. Keep these in mind if you need a flow pump.

 

[ShawnSaucier]

Not sure about going through the bottom. Maybe more of a over the top manifold feeding either lock line or some seaswirls. Or a few on the back wall typ idea.

 

[jda]

I forgot about Sea Swirls, but those are great too. ...just keep the velocity up and use 1/2" if you have to.

Over-the-top can work, but if you can drill the back for the intake, that is better, IMO. You can have start/stop issues if air gets into the line with an over-the-top. This is not hard to mitigate, but something to think about.

 

[ShawnSaucier]

I would definitely do the intake on the back. As much as I love the idea of going through the bottom to have flow aimed at the reef, I am a bit nervous about doing it. But when I have seen it, the results are great. Just need to lear more about it

 

[Fin]

Just to show you that you don't have to turn the tank into swiss cheese, these are some pics from when I used a closed loop on my old 140 (built in 2006). The only hole I drilled was in the center back panel for my intake. The system was run by one of the older ReeFlo Darts and an OceansMotions 4Way valve.. I had two of the returns at the upper front and two that ran down the back wall (with black pvc), under the sand bed to the two front bottom corners. I took some rubble rock and hot glue and covered up the bottom returns (they were eventually covered up with GSP.

You can barely see the black PVC pipe down the back wall. The 4Way valve fired two returns at a time - bottom left & top right & bottom right & top left.

The 4Way plumbing

One of the bottom returns

And the tank after it matured. I did add an MP-40 once it started to fill in, but the Dart provided a lot of flow in this 48" tank.

 

[jda]

If it makes anybody feel better, I had to replace a bulkhead near the bottom of a 240g. I just emptied the water into rubbermade containers, moved 2 rocks to get to the bulkhead, changed it in about 2 minutes, put the rocks back and filled it back up. It took longer for the fresh PVC glue to dry than it did to replace it. 10 minutes out of water did nothing to my acropora. Fortunately, I had access behind the tank. If you are really worried about this, you can put the intake near the top and use a 90 and some pipe to get it down far enough so that it does not draw in air.

 

[ca1ore]

What is pump-native pipe?

Sorry, thought it self explanatory ...... Simply maintain the thread diameter through the plumbing system. So if the native threads on the pump are 1 1/2", use that diameter pipe throughout.

As for holes through the bottom of the tank, I just think it's unecessary. Lots of nozzles through the bottom might seem like a cool idea but it's really does very little in terms if incremental flow. I don't personally like over the top pipes so I just plumb the suction and returns for my CL at the top of the back. That way, if I need to service a bulkhead, it only requires draining down about 6" of water.