Closed Loop Dilemna

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

Should it be patched or ran with?

  • Patch it!

    Votes: 0 0.0%
  • Use it like it is!

    Votes: 0 0.0%

  • Total voters


Aquarium Advice Freak
Feb 14, 2005
Salem, OR
Okay... here's the tank and the question... Should I patch the bottom and drill new holes in the side for a closed loop, or go with the bottom holes?
Sorry, I miss-voted! Idiot!! I say USE IT. What's the problem you see with using as is? Of course, you'll need an intake up along the back but those bottom holes will make fine returns. Also, I saw a tank with four returns that blew up from the bottom - very cool. You can extend the other ports near the top of the water line as well, and point them into (almost) the current from the bottom

So, I'm not sure hat hole pattern ahs any negatives. Anybody?
Still contemplating it all right. I'm soooo done with the stupid 55 undrilled tank, it dumped 6 gallons onto the floor last night because the overflow didn't want to cooperate. I will be moving all the coral to my 58 Oceanic tonight, and switching the halide to the 58 and the pc lighting to the 55. It's closing out on Ebay today, I hope to get something out of it but I'm done messing with it.

Here's my take on drilling more holes vs. using the holes here...
It won't make the tank any weaker because the holes in it are would be patched over with acrylic and acrylic bond, in effect, they're getting filled with 3/8 inch thick acrylic circles, bonded there, then patched with 1/4 inch sheeting from the inside of the tank. So that's not an issue. Acrylic is not like glass... it's repairable.

Having returns in the bottom seems like a good idea except for a couple reasons, and here's my take:

A. If a pipe broke or started leaking, I'd have to take everything out to get to it.
B. If I needed to adjust something, I'd have to take everything apart to get to it.
C. If it had a weird failure, it could drain my entire tank.

On the other hand, it would sure be easier just to use the holes for returns and build an internal overflow like the one on my Oceanic.
Holes in the bottom will get better drainage flow than holes in the back. Gravity will be on your side. It's only the closed loop and return lines to question.

A) You pretty much have to move all the occupants any time you do major work on the tank no matter where the holes are.
B) Depends on what you need to adjust, a standpipe can just screw into the bulkhead, to change it just reach inside the overflow box and unscrew.
C) True. This a tradeoff between safety and good drainage. If your patch has a wierd failure, it could drain the whole tank too. I'd rather invest in high quality bulkhead fittings than worry about the re-patch and re-drill.
As to A... I might have to move them, but if the plumbing is in the bottom, I have to REMOVE them all. If it's plumbed through the back, I only have to drain it to the point it's plumbed, and then move the rock from the back, from the area of the plumbing and blamo, I'm there. What worries me is that under the rock a return might get broken or cracked and I'd have to tear everything apart to get to it.

B with the standpipe, I'd have to cut a hole in the top to fit it into whatever overflow box got put inside, or I'd follow Brendan's suggestion (Kudos for that) and build an external overflow box. (Not those stupid CPR types but an actual megaflow style overflow that just happens to have the box on the outside of the tank)

C. The patch could only have a weird failure if the acrylic itself were melted. Weld on basically is a weld... with the holes filled and patched over, unless I were incredibly incompetent and missed the area entirely, there's really no chance of failure. See, the holes aren't just being filled... a patch bigger than the affected area is also being applied. I don't know how familiar you are with weld on applications, but the stuff is pretty incredible. I built my sump for the 58 tank and I've dropped it, moved it with rock in it, had big things land on it (during moving) and the thing's never so much as looked hazed. I'm very confident in my plastic working skills.

Now this doesn't mean I've quit debating... I'm just playing devils advocate here. I want to really look at this from every direction. Personally, I think the location of the holes is awesome, especially if I built a drilled pvc rack into it, with a few loc-line returns around the edges where they could be directed for flow outside the rock, but still concealed by the rock. This tank is going to have roughly 300lbs of rock in it before I'm through, so I really need to consider ease of maintenance. Which is the main reason holes in the bottom make me uneasy. Originally I planned on using them, until talking to some of the people locally where it was almost unanimously suggested that I patch and redrill. I would like to have some soft flow in the rock, and some decent current in the open areas, with a couple returns near surface for surface agitation. I've tossed putting two overflows in, with two surface returns from those, and having the rest of the returns be the pvc rack and loc-line.
Up to you, you sound like you're really leaning towards redrilling. I've just heard alot of people advocate bottom drill over side drill.
Well convince me! What were the reasons for bottom over side? As to the gravity part... what I've always heard and see as common sense is there's no good reason to have a intake from the bottom unless it's in a overflow box, because the risk of draining your tank is too high. And most closed loops are too strong to be ran through a overflow box, so the intake for the closed loop has to be in the side. Part of this reason being so that you don't lose animals and part being so you don't lose your tank if something happens. But tell me, what are the compelling reasons that make you prefer bottom over side?
I told you before I did not like drilling the bottom. You already stated the reasons that I told you I felt that way. One thing to consider also is that regardless of the fact that "you know what you are doing" or not the patched holes will not be bearing pressure since they will be against the stand. Chewing gum would probably hold it. :D
Yeah, I'm thinkin patch n drill is the way to do this. It'll make building the stand a lot easier too. And that external overflow box idea is just the bomb... Brendan, you got me convinced. Between you and the local reefers (I said reefers not reefer) I really just don't see any reason to risk losing all the water. I'd rather plumb a reef rack in from about 3/4 up the back and working its way down, with some loc line coming in from a little higher. Been checkin reef central and they got a thread on manifold style closed loop plumbing that is kinda interesting. Either case... Thanks all for your input!
A closed loop system it's not so much an advantage, but the sump drain should be on the bottom. The fewer turns on the way from the overflow box to the sump, the greater the capacity and the lower the risk of clogging.

Where will the closed loop pump be located? Will you be able to reduce the number of elbows with one setup or the other?

Here's one guy's idea of what to do with bottom drilled holes:

Latest posts

Top Bottom