DIY closed loop system

mike31154 · #1 12-28-2009, 03:38 AM

Tunze is a company that primarily manufactures powerheads and wave boxes for water movement in marine tanks. I think they also make skimmers and a few other things. Anyhow, a Tunze powerhead is placed in your tank for water movement and can be situated pretty much wherever you want to create the flow you need. No holes required in your tank to use them or any other powerhead such as a VorTech or Koralia.

A closed loop is essentially a plumbing network which draws water from one area of your tank through a bulkhead (requiring a hole or multiple holes through the glass) and delivering it via an external pump back into the tank for flow, either over the top or through more bulkheads through the glass in several other locations. It can be fairly simple or get quite complex, depending on your flow requirements. Generally once a closed loop is set up, there's little you can do without major rework if your requirements change. A closed loop is separate and independent of your overflow, sump and return pump if so equipped. A conventional powerhead is easily removed and relocated although more unsightly in the display. A closed loop can be virtually hidden if done properly, although multiple outlets are required to create adequate flow in all areas of the tank since the openings are typically small with concentrated flow. This is where a Tunze or VorTech powerhead have a bit of an advantage since the flow is more broad and they are easily repositioned if required.

Lots of debate re closed loops vs powerheads these days. Each has its advantage & disadvantage. In the end I think it boils down to personal preference, since adequate flow can be provided by either method if implemented properly.

ZachAttack · #2 12-28-2009, 03:43 AM

Ok, so the whole tunze vs closed loop arguement is strictly on of flow. if you want to hide your refug. skimmer, filter, etc. then you need a closed loop section...

mike31154 · #3 12-28-2009, 03:54 AM

Quote:

Originally Posted by ZachAttack

Ok, so the whole tunze vs closed loop arguement is strictly on of flow. if you want to hide your refug. skimmer, filter, etc. then you need a closed loop section...

Yes and no. Yes it's a flow argument and No you don't need a closed loop to hide your refugium, skimmer etc. As I mentioned in my earlier post, the closed loop is a separate system from your sump and return pump. The sump and/or refugium is where you can place your skimmer, heaters etc. It has its own return pump but it is in fact a kind of 'open' loop because of the overflow typically used to drain the display tank water to the sump and refugium. The 'closed' loop for flow is 'closed'. Bulkheads for intake, pump inline, more bulkheads to discharge the water back into the display. Totally separate and independent of the sump/refuge circuit. This is one of the potential disadvantages of closed loops, all the extra holes required in your tank.

ZachAttack · #4 12-28-2009, 03:58 AM

OK... I understand what you are saying now. However, can you not just use the lines from your sump pump to create your flow if you Tee the lines and put the returns in multiple dispersed locations??

mike31154 · #5 12-28-2009, 04:06 AM

I don't currently run a sump so I'm just going by what I've read, but typically the flow from your return pump and sump is insufficient for most marine set ups. It's more for filtration and extra water volume than for flow. Some folks run water faster than others through their sumps, but for hard corals, supplemental flow is almost always required, either via powerheads or closed loops.

Even though I don't have sps corals, I run two VorTech MP40Ws in my sumpless set up. The flow from these two powerheads does a great job of keeping detritus etc from settling anywhere in the system.

ZachAttack · #6 12-28-2009, 04:09 AM

ok, thanks mike, could you not just go with a really high gph pump for your return?

mike31154 · #7 12-28-2009, 04:32 AM

You could, provided your overflow can handle what the return pump delivers. If not, you'll have yourself a flood, followed by an empty overflow, followed by a starved return pump, followed by a seized return pump or tripped circuit breaker, followed by.... you get the idea.

Most overflows are not able to deliver the drain capability for an oversized return pump and too much flow through the sump causes all kinds of other issues. Closed loop is not as limited since no air is involved, it's kind of like a full siphon on steroids.