Closed loop circulation

[TriMax]

I need to drill holes for a closed loop system. I have seen holes in the back for both the outlet and inlet to the tank. I have also seen holes in the bottom of a tank. Any comments on which is preferred? Tank is 300 gallon - 96x30x24.

My plans are to use a Ampmaster Dolphin 4700 pump.

What did you do? Would you do it differently if you could start over? I am open to other suggestion also.

Thanks

Eddie

 

[Fiziksgeek]

Is this an existing tank, or one to be built?

If its glass, just remember that the bottoms are usually tempered, and can't be drilled!

holes on the bottom are a risk. Many people have them, and some will even admit that it makes them nervous. If you have a bulkhead failure, your entire tank will drain. If the holes are on the back and the same happens, the tank will only drain down to the level of the hole. Will still be a huge mess, but atleast you will have some water left in the tank still so you wont loose all of your livestock...

 

[TriMax]

More info

The tank is built. I transport it home this Saturday. It will be about a 7 hour round trip. It is acrylic - 3/4 inch sides, front, and back with 1/2 inch top and bottom.

What I have seen in the other tanks was three holes about 1/3 the way up from the bottom in the back for the discharge from the tank and at about 2/3 the way up the inlet holes to the tank are placed. At those locations, a bulkhead leak would certainly make a mess.

I was just wondering if that was the way to go, or if someone had a design that worked better. I like the idea of having the extra flow without having it go through the sump.

Thanks

Eddie

 

[Fiziksgeek]

I agree. The only other way to get the flow would be power heads. I am setting up a 210. Mine is glass, so I can only drill the back. I am planning to use the 1/3 and 2/3 height measurements. You have more flexibility with the acrylic. Good luck!

 

[sidewinder770]

I have my closed loop intakes and outputs drilled through the bottom. I have 2 closed loops with 4 outputs. I have had bottom drilled tanks for many years- both glass and acrylic and never had a problem. Of course on glass it has to come pre-drilled to make sure it's not tempered but you don't have to worry about that since you have acrylic. I know a lot of people don't like drilling the bottom for fear of a bulkhead or pump failing but I wouldn't hesitate to do it and if I do another tank it will probably be through the bottom as well. In either case, if something fails, your going to have a mess but I don't think one is more prone than the other to fail.

 

[TriMax]

Sidewinder

Why do you use holes in the bottom instead of in the back? Do you use the bottom holes for both inlet and outlet?

Thanks

 

[sidewinder770]

Yup- Both my closed loop inlets are on the bottom as well and 4 for outputs. I also have 2 holes in the bottom of each overflow for intakes and returns. In total I have 10 holes in the bottom- 4 are 2" bulkheads and 6 are 1.5" bulkheads. One of the main reason for doing it in the bottom is access- my tanks have always been up against a wall and to put them on the back would be a pain to get to (not like I can just slide a 375g tank out to get to them) and having them in the back would also push the tank farther into the room. Of course not having any equipment under the tank makes a big difference as well as I'm not worried about taking up space with plumbing.

You may have seen this pic already but here is the plumbing under my tank-

 

[dgasmd]

I have had holes in the back and bottom in glass and acrylic. I currently do have both. However, if I was to do it all over again, I would not drill the tank, acrylic or glass, except for the very top of the side panel for an overflow. The reason is that if there is any failure in the plumbing, bulkhead, or pump's seal, the entire tank will drain to the lowest point, which is the bottom = empty tank. In retrospect, I would do it very differently, and given you have acrylic it would be even easier. I would put the bulkheads on the eurobrace of the tank and bring pipes down for returns and for the intake. Have the manufacturer build you a 3 sided cover in balck acrylic (assuming the back of the tank is black) that you can glue a pipe holder to the back of it and put over the pipes and hide them. Then, drill syphon break holes in all the plumbing right below the water line. That way, you have a system that if any failures occur, it will drain very little of the tank's water. Also, it makes it very easy to disconnect the intake screens for cleaning.

 

[TriMax]

dgasmd

I really like that idea. Since my overflows are on the back the tank will sit about 6 inches or so from the wall anyway. I am not sure what you meant by a 3-sided box, but a think a overflow that is the length of the tank with several bulkheads for inlet and outlet can work.

Thanks for your input!!

Eddie

 

[TriMax]

Stupid, Stupid, Dumb, Dumb, Stupid, Stupid. I was planning to drill holes in the pipes while they are in the overflow box. This would work for the outlets from the tank, but never would have worked for the inlets to the tank. Water would be spraying everywhere and would need to flow back into the tank or down the overflow outlet to the sump. Stupid, Stupid, Dumb, Dumb, Stupid, Stupid.

I will go back to two overflows and run the plumbing up, over, and down into the tank from the back. I might need to get some more black pipe.

Oh well.

 

[dgasmd]

<a href=showthread.php?s=&postid=7333734#post7333734 target=_blank>Originally posted</a> by TriMax
dgasmd

I really like that idea. Since my overflows are on the back the tank will sit about 6 inches or so from the wall anyway. I am not sure what you meant by a 3-sided box, but a think a overflow that is the length of the tank with several bulkheads for inlet and outlet can work.

Thanks for your input!!

Eddie

The only down side to doing it all through the overflows is that if they are internal the larger number of holes next to each other in close proximity makes the pane very weak in that area. If it is the bottom pane and it develops a crack, the entire tank will still leak through it. If you have an external overflow, that is a good way of doing it. However, you still will have a lot of plumbing right next to each other in a smaller box, so god forbid you have to undo something it will be a huge pain in the arzz to do since you have all the pipes crammed in there. Having them spread out through the back pane makes it much easier and makes it more versatile in how you can do your plumbing.

What I meant by a 3 sided box was simply something to put in front of the pipes as they come in and out of the tank over the back pane inside so you don't see them at all. Just a cover.

 

[prugs]

I did not want to drill my 210AGA RR.
I use the standard overflows for the sump/fuge with a Posiedon PS2 pump.
I did a closed loop over the top on the back of the tank for circulation with a Oceans Motions 4-way & a Reeflo Dart.
No regrets.