Please help with closed loop design

tommyb · #1 (**permalink**) 11-19-2009, 08:28 PM

I am starting to put a 240 together and it will most likely be fish only. It is an acrylic 8'x2'x2' and has dual overflows in the corners. It already has one hole drilled in the center of the back but I am wondering if I need more than that or if it should be larger. I believe it has a one inch bulkhead in it.

The returns were designed to go through the top of the tank. Should I keep them there or drill more holes in the back for the return. How many?

The pump I will be using is a Reeflo Hammerhead. This pump puts out 5800 gph @ 0'. Should I build a shelf to put it closer to the tank or just put it on the ground. The top of the tank is about 6' off of the ground.

Sorry for all of the questions, any and all opinions will be appreciated. Here are a couple pics of the tank.

John · #2 (**permalink**) 11-19-2009, 08:39 PM

I would suggest adding a sea swirl. I've heard good things about those.

Also, if you don't want to add a sea swirl you could uhmm... uhmm... honestly Tom_B I've got nothing... I had to buy a pair of MP40s because I didn't want to do another closed loop...

tommyb · #3 (**permalink**) 11-19-2009, 08:44 PM

Quote:

Originally Posted by John_OS

I would suggest adding a sea swirl. I've heard good things about those.

Also, if you don't want to add a sea swirl you could uhmm... uhmm... honestly Tom_B I've got nothing... I had to buy a pair of MP40s because I didn't want to do another closed loop...

I am trying to stay away from power heads but if I was to get one or two I would definitly go with the MP40s since they don't really stick out like the other ones.

My initial thought was 2- 1" drains going into a 1.5". Then have 4 returns, 2 on the top and two on the bottom but have them staggered. I have no idea if this is practical or not but just though I would throw it out there.

ryan72 · #4 (**permalink**) 11-19-2009, 08:44 PM

Are you going to use the 1" for the pump intake? It will need to be bigger. I think the hammerhead needs a 1.5" That is a seriously strong pump. You'll not notice a difference between it being on the ground and on a shelf. I saw use 4 returns and a OM 4 way for some great movement.

I use a smaller sequence pump on a 4 way to 4 returns. Each is split twice inside the tank to give 8 returns. Each are very forceful and do the job nicely.

I like the idea of less holes drilled below water line. It is safer and looks better too. If you can widen out the 1" to 1.5" I'd use that as the intake-but that can be hard to do.

tommyb · #5 (**permalink**) 11-19-2009, 08:52 PM

Quote:

Originally Posted by ryan72

Are you going to use the 1" for the pump intake? It will need to be bigger. I think the hammerhead needs a 1.5" That is a seriously strong pump. You'll not notice a difference between it being on the ground and on a shelf. I saw use 4 returns and a OM 4 way for some great movement.

I use a smaller sequence pump on a 4 way to 4 returns. Each is split twice inside the tank to give 8 returns. Each are very forceful and do the job nicely.

I like the idea of less holes drilled below water line. It is safer and looks better too. If you can widen out the 1" to 1.5" I'd use that as the intake-but that can be hard to do.

It is an acrylic tank so turning the 1" intake into a 1.5" intake should not be too hard.

I don't think I want to use an OM or anything like that since it will only be fish in there without corals, but maybe some change in flow would be nice.

Do you think I should keep to of the returns going through the top and then split those with locline into 4? Should I include 2 more returns near the bottom as well?

reefone · #6 (**permalink**) 11-19-2009, 09:07 PM

my 8' 240 g is drilled for a cl but i sealed them off. kind of wish i didnt. its hard to get good movement down low in the tank. im using 2 mp40 6-8" under the waters surface on the back wall. my tank is drilled with 4 holes on the bottom 6" in from the front glass and 4 holes across the back 8" up from the bottom. i think i should of used the holes along the back twords the bottom to help keep the junk stirred up better.

dentdominator · #7 (**permalink**) 11-19-2009, 09:20 PM

Tom, I would place the pump right behind the tank or on the side of the tank on the same level the tank sits on.

Then build a manifold so you can independently control the flow to each of the 6 returns.

I would place a return on each side and 4 across the back 3" or so below the water line.

Then drill for the pump intake around 6" or so below the water line.

dentdominator · #8 (**permalink**) 11-19-2009, 09:23 PM

OR you can drill out the bottom and place the pump on the ground. If you do the bottom it will be a much cleaner job with the plumbing. Just like TomToro's.

tommyb · #9 (**permalink**) 11-19-2009, 09:26 PM

Quote:

Originally Posted by dentdominator

Tom, I would place the pump right behind the tank or on the side of the tank on the same level the tank sits on.

Then build a manifold so you can independently control the flow to each of the 6 returns.

I would place a return on each side and 4 across the back 3" or so below the water line.

Then drill for the pump intake around 6" or so below the water line.

I like this idea. Thanks.

Tankster · #10 (**permalink**) 11-19-2009, 09:30 PM

thinking about oceans motions at all?

tommyb · #11 (**permalink**) 11-19-2009, 09:32 PM

Quote:

Originally Posted by Tankster

thinking about oceans motions at all?

Probably not.

jahorgos · #12 (**permalink**) 11-20-2009, 08:28 AM

2 MP40ws and no closed loop is what I would do. Closed loop systems are too limited and destroy the resale value of a tank.

tommyb · #13 (**permalink**) 11-20-2009, 10:30 AM

Quote:

Originally Posted by jahorgos

2 MP40ws and no closed loop is what I would do. Closed loop systems are too limited and destroy the resale value of a tank.

Do you think that would be enough flow in a tank that size?

I don't plan on selling this since I would have to take down the wall to get it out, but you never know.

barcuda71 · #14 (**permalink**) 11-20-2009, 10:44 AM

Since I know you stated that you are going to use the Hammerhead for your closed loop, I thought I would explain my experience with using the Hammerhead as a return pump. I am currently using the Hammerhead for my 300, same dimensions as yours other than it is six inches taller, for the return on my setup. I have the return going from 1.5" to 1.0" as it enters my tank from the back. There are six 1.0" bulkheads that are used for this. The pump sits on the ground about four feet from where the bulkheads are located. I have the Hammerhead throttled back about halfway right now, until future plans, since I can't remove the water fast enough. This pumps jams. There are three overflow boxes, two in the corner and one in the center that contain both an 1.0" and 0.75" drains to the refugium. For my closed loop, I am using the Dart which feeds two 1.5" returns through the bottom of my tank. I have each one of the returns splitting into two using loclines. Now looking back after cutting holes for the closed loop, which are located more or less in the middle outer of the tank, I think I would have rather placed the holes further towards the back of the tank on the bottom or towards the bottom of the tank on the back wall since it was challenging to disguise them with aquascaping in my tank. I don't know if anything here I wrote is of any help for you, but that is how my tank is setup. If you havent' seen my build, here is the link: 300 Gallon Facelift

reefone · #15 (**permalink**) 11-20-2009, 10:52 AM

Quote:

Originally Posted by tommyb

Do you think that would be enough flow in a tank that size?

i dont think it will be enough flow. ive got 2 k3's along with my mp40's.