Closed loop tank

[pulpfiction1]

i would like to learn more about the closed loop systems,best design,how it works,etc.......

 

[shayneh]

LOL I'm adding one in my current tank build (75g display with Reeflo snapper on the closed loop @2500gph). if you get it figured out or come across anything let me know.... There isn't really a set way for designing them and from what I can tell most folks are just winging it but they solve a few problems.

-Increased flow in the tank keeps detritus suspended (no different than powerheads)
-running an external pump keeps heat out of the tank
-clean look with no equipment hanging on the sides/back of the tank
-because there are no cords in the tank there is less risk of electrocution or stray voltage...both aren't good for livestock either.

**This is the big one for me since I have gotten a jolt from more than one faulty powerhead (really sucked because there were more than one powerhead in the tank both times and knowing you might not have picked the right powerhead really messes with your brain when you have to put your hands in the tank again). When you think about it your powerheads get pulled around by the cords and bumped around and are they are just encapsulated in epoxy. When that's the only thing keeping you from dancing the ultimate jig it makes about as much sense as playing catch in a saltwater pool with an electrified toaster in a ziplock. The only way to avoid this is using expensive powerheads which either use low voltage in the tank (12v Tunze or Korallia's) or keep the electrified motor out of the tank (Vertech mp10-60). When you compare the costs for similar amounts of flow it's really a wash and so it all comes back to the other advantages that a closed loop offers.

The only disadvantage is that a closed loop pump draws more electrical current than your higher end powerheads. Take for example my Reeflo snapper moving 2500gph through 4 returns @ $230.00+ install drawing 98watts vs a Vortech MP40 moving 1000-3000gph @ $500.00 drawing 28watts through one adjustable speed source or 9 Maxi jet 1200's moving 2565gph @ $230.00 drawing 180watts and 9 returns.

LOL there are always trade offs and I decided with the added cost and hassle of plumbing the tank for a closed loop it's the better choice given my desire to have a clean look. 

 

[pulpfiction1]

so you still use a sump and the closed loop is just  circulation?not only moving water in but re-moving it out at the same time,is the correct theory?also no air in lines so less head pressure i assume?this seems like a logical way to approach water movement,is there a min number of holes or can a couple do the job?ive researched this some since reading on here i assume was you mentioning you  were gonna build one.would you filter the out ports?my external pumps suck up crap like snails and can make lots of noise.
so many questions i know,let me see how you set yours up once you have it up please?

 

[shayneh]

I will be doing a build thread to coincide with the Z&P grow out contest. You still run an open loop (drain from tank to sump and back) system in tandem with the closed loop but the closed loops only function is to move water like a powerhead (so no filtration). To keep crud out of the lines I will be placing the 2 X 2inch intakes for the pump near the top 6-8inches of the tank and have 2 X 1inch returns on the bottom pointing into rockwork and 2 more on the back mabye pointed toward the top of tank for proper gas exchange and to keep detritus suspended until the overflow for the sump can deal with it. That coupled with a 500-700gph return from my sump give approximately 35-40X turnover. Also I plan on running bare bottom so there is not too many small things to worry about getting sucked into the pump intake. There is almost no head pressure as the siphon pressure from the intake side is almost equal to the pressure on the outlet side provided you use the right diameter piping for both ends of the pump (friction in pipes also contributes to head loss). Number of holes depends on the pump and the diameter of pipe required to reduce flow to the recommended 4ft/s for each outlet so your not blasting away corals. Cool part is you don't need to drill your tank to do this as there are lots of plans online for over the top intakes and return manifolds. Just don't use a crappy inefficient pump.....don't want to bash specific makes there is enough info online to find out problems people have had using the less expensive pumps (leaking seals especially) and most places post the wattage draw of each pump.