Complete newbie requesting help with first octopus setup!

[djkaty]

Ok, I thought the solutions were similar. I can get the person who was driving me to Tess tomorrow to drive me to the glass master instead. So, what I should really do is take the overflow box with me and say, "cut a section of glass with holes like this in the same place", basically? Then silicone it to the back of the tank. Is that right?

 

[DWhatley]

Yes, if you can align (center to center is not the concern, just being able to align the holes so BOTH bulkheads will pass through BOTH the overflow and the tank and be straight, it cannot be angled). You should also silicone the glass piece to the back of the tank just to avoid slipage (sealing is not the concern here, the silicone is just to keep the heavy back plate in place and avoid breakage should you remove the bulkheads at anytime).

It's fixable Katy, but like anything else any more, a little more work and frustration than it "should" be. Your a programmer so just think of it as bug the is challenging but fixable .

 

[djkaty]

Both bulkheads will fit through both holes with it horizontally level, just about, so that is ok All makes sense.

 

[DWhatley]

OK, that is what I thought initially so the fix is just to reduce the tank holes and relocate their centers using the overflow and a backing.

You don't really need to think about an alternate to think about but you might consider siliconing a piece of glass to the inside of the tank (the glass pane would be the size of the overflow box and drilled identically to the outer piece). This WOULD be a sealing surface. Then you could attach the overflow box with just the bulkheads as it was in the original tank. The advantage is, as Joe mentioned, using silicone on glass to glass rather than glass to acrylic.

 

[CaptFish]

Cut the back of the overflow box off and glue the box to the tank..

 

[DWhatley]

That won't work CaptFish because it is the holes in the glass that are missized. Additionally (if you added the resizing glass panel), holding the box on with just glue (silicone or whatever) won't last long.

 

[CaptFish]

I keep thinking she can get the proper size bulkhead

cam you screw it all together and take a picture of the gap you have left over?

 

[djkaty]

I had already thought of that D I was wondering if the sharp glass edges would be a problem for the inhabitants if the new glass piece is stuck onto the inside of the tank, and also how aesthetically problematic it would be.

Anyhow there is about 40mm clearance (on the outside of the tank) from the top of each hole to the top of the tank, which is plenty; inside the tank the picture is different. The hole towards the center of the back of the tank is situated under one of the glass pieces which supports the lid, and there is only 16-18mm clearance there. On the overflow box itself, the distance from the top of each hole to the top of the box is a mere 9mm.

None of which really matters except that if it's going on the inside of the tank I need to have that in mind before I tell them how big to make the piece of glass.

 

[djkaty]

CaptFish if I do that you won't see anything because the nuts on the bulkheads completely obscure the holes.

 

[CaptFish]

oh....but if the nut covers it then it shouldn't leak....I'm missing something here...

 

[DWhatley]

I think CaptFish means without the overflow box attached or a photo from the back of the tank.

 

[djkaty]

Sorry Capt, bear with me, I'm extremely tired today and thinking of just going to bed. If you tell me what it is you want to see exactly / what aspect, then I'll take a pic.

 

[Joe-Ceph]

Joe, I think that is pretty much the same (other than using glass - good idea if she can get it drilled) idea as my original sketch - correct me if I missed something - instead of acrylic).

Sorry D, I missed seeing your sketch. Where is it?

Neal also confirmed that a gasket on the outside of the tank does nothing.

YIKES! Not true.

Katy, the back glass piece [...] is NOT for sealing the tank, the silicone on the inside between the overflow box and tank wall will seal that gap and the bulkhead will seal the overflow.

Sorry D, but no, that's not accurate. It would be true if the nut part of the bulkhead fitting were on the outside of the tank, but it's not. The bulkhead nut goes inside the overflow box, which is inside the tank, and the flange, with the important gasket on it, goes on the outside of the tank. Take a close look at Katy's picture of the bulkhead parts. You'll see what I mean.

The only two seals that really matter, will be the gasket on the flange of the bulkhead (which will be on the outside of the tank) and the silicone holding the glass piece (with the two 45mm holes drilled in it) to the back of the tank (also on the outside).

The silicone between the overflow box and the inside of the back wall Isn't really necessary (so forget my previous advice, and don't glue the box in (unless you are worried about it slipping out of level)) Water is going to leak along the threads of the bulkhead through the hole in the overflow box, through the hole in the back of the tank, and then be stopped by the two seals I described above, circumventing any silicone or gasket that are inside the tank. Water will pass between the threads of the nut, and the threads of the bulkhead, which are both inside the tank, as if the nut weren't there.

D was right about it being easier to use one piece of glass instead of two, as long as the holes are drilled to match the holes in the overflow box, I should have seen that. using two pieces is needlessly complicated. She's also right that this could be done using acrylic instead of glass, although it needs to be thick enough not to bow or crack. Glass is better, but acrylic might be easier to work with.

 

[DWhatley]

Joe has apoint that I have to think about when putting these in backwards. I need to remember which tank we decided to do this with and see which side is actually water tight but what Joe is saying makes sense. The water pressure on the inside helps to seal the tank, this would not be the effect (and there would be a pulling effect from the water flow) if the seal is on the outside but I don't know how effective the seal is using the nut vs the flange. I believe the nut is flush and would provide the same surface but it is hard to know without looking at the unit.

 

[djkaty]

I actually just tested what Joe said 'trial of fire' hehe, by using a gasket on only one side - the outside, and screwing the nut on inside with only the acryllic washer (through both the overflow box and tank holes). He is right, no leaks - only the outside gasket is needed therefore.

So having said that, the new glass piece _must_ go on the outside with the gasket after it to make a seal, right? Otherwise water will just continue to drip out of the larger hole as it was doing earlier in the week.

(Note: it was easy for me to test because I just centerised a single overflow and tank hole over each other with the gasket centerised too; the other hole in the overflow is siliconed over now for the moment. When having the box this way though, it is not possible for the other bulkhead to fit through the other tank/overflow hole set because they overlap slightly. If I didn't centerise the whole I put the bulkhead through to test, then both sets of bulkheads would go through but it would leak - which is the problem I had on Monday when I realised the hole distances were wrong).