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40B bowing--is this normal or too much?

2K views 15 replies 6 participants last post by  PlantGate 
#1 ·
So I've recently set up a second-hand 40 breeder. It's been full and running for about 3 weeks. But today I went to put on a new glass top, which is cut poorly and doesn't fit well, and noticed a significant (to my eyes) bowing at the front/top of the tank. (Note: in the pics below, the separation on the near side is mostly due to the poor fit of the glass).

I'm really hoping I wasn't sold a reptile tank instead. It's been sitting in storage this last year, so I cannot remember if I asked the original owners what it was used for. The glass appears to be about 5-6 mm thick (pic below) and about as much silicon sealant as the rest of my tanks.

I did notice that there is a break in the top trim. It's not really a crack, I don't think, because it's fairly uniform. What really scares me is I can physically "push" the glass back a good 2-3 mm.

I use an AC70 HOB so that puts some pressure in that direction. Otherwise, I checked and the tank is level.

I'd rather not have a major leak on my hands, and neither would my neighbors below me. Is there any way to know for sure if it's going to be safe?

If not, maybe I'll just reconfigure it for a paludarium...
 

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#6 ·
Thanks!

If I'm replacing only the top trim, do I need to drain it completely? Curious if new silicon will dry correctly on the old, inside silicon...and I'd prefer not having to do another tear down after moving a few weeks ago...but safety first!
 
#9 ·
Honestly I'd never trust it again as a full aquarium. You certainly could get a new rim, but how much stress was on that glass before you get the new rim? What damage might it have done? It might not seem like a lot, but 40 gallons is a ton of water to have hit the floor at once. It's just not worth the risk IMO, especially when you can pick up 40 breeders for relatively cheap. It would be way cheaper than water damage to your walls or floor.

That's personal opinion though. I know people who have fixed tanks like this with no issues whatsoever. I also know people who had disasters. I'd say the successes outnumber disasters, but to me it just isn't worth the risk
 
#10 ·
All depends on the damage as you say and if you don't know how to properly assess a tank I would agree better safe than sorry. However doing so is very easy. Simply look straight through the overlapping glass with the aquarium full along the corners and inspect for what looks like bubbles or tearing in the seam. It is normal to have some flexing of the glass on any tank it doesn't weaken the glass but it can tear the seam. By seam I mean the silicone directly between the 2 pieces of glass not the crap smeared up the sides. All the strength comes from that bond between the seams. Its not like stress on glass causes it to get weaker however a tear in the structural parts like the seams would definitely be cause for concern but as I stated this is quite easy to assess. I have built many tanks over the years so I guess I have more comfort in replacing a rim than most people but it really is not rocket science. I have also repaired quite a few freebies for this exact same situation. I mean its not my decision and the only 100% guarantee is to throw it away but the only 100% guarantee with having even a brand new aquarium is not to not buy one.

Personally for a 40B you can probably pick one up on $1/gal sale for about the same cost as fixing.

Dan
 
#11 ·
Thanks all. I certainly do not want a major water catastrophe.

But I'm not a very handy person either, so I'm wary replacing the trimming.

I can't say how much damage has been done. Like I said, it's only been up and running for the last 3 weeks. It was an "upgrade" from a 20 long after a move where I now have more floor space. It would be a major PITA to have to tear down and toss this one. Catching fish is the worst.

I don't think there's a $1/gallon sale until later this summer, at Petco at least. Unlikely I want to wait it out until then. 40Bs are around $90 at Petsmart...and I have a hard time trusting a local Craigslist ad right now.

Any other thoughts on whether it might be safe <1/2 full longer-term? Again, not sure how much, if any, damage has been done to the seals...but either way, it's not something I can replace right away.

Argh, decisions...
 
#12 ·
It's a risk, but if you are willing to take the risk, go for it. You can run half full and it should be ok. As Dman mentioned, check every seal between the glass panes. If you are starting to lose any seals there, that's a big problem. There should be a layer of silicone between each glass pane with little to no bubbles. If you see any separation of the silicone from the glass between the panes, I'd be concerned. Also inspect each glass pane for small cracks. They may not be leaking, but it's possible to get stress fractures in the glass that start as tiny little things and end up in a broken pane.

Replacing the top frame is a good alternative if you are confident there is no seal damage or glass damage. You really don't have to be that handy. It's just a razor blade, some acetone, some silicone and patience.

Honestly, the likelihood is you should be fine running half full. Again, as Dman said, there are no guarantees, even if you buy a new tank. Any tank could fail. A lot of this will be about your peace of mind. You know the tank has undergone some stress. It's likely not critical stress and the tank should be fine running at half capacity. But if that unknown is going to keep you up at night, and you think buying a new tank would alleviate that concern, to me, it's worth it. Ultimately you have to make this call. No one can say for sure that it's going to be fine. By the same token, no one can say it's definitely going to fail either. In fact, we can't even put odds on it. Just do your best due diligence on the current state of the tank and make your most educated decision.
 
#14 ·
Do you know if the top rim cracked because of the bow, or it just happens to be cracked? If it is the first, I would totally ditch the tank ASAP. If it's the second, I would still ditch the tank, but may consider running it at a lower water level and wait for a $1/gallon sale.

I am sure it would likely be fine at 1/2 full but I personally wouldn't do it. It's a tank that can be had for $40, and can do far more than $40 of damage. To me, that's really the basics. I know it's a lot of work to replace a tank but it does give you piece of mind.

Now, I am not saying this what you should do, it can be repaired, but since you don't seem to know why it happened, it's just not what I would do.
 
#15 ·
I noticed the crack before adding any water. In my naivety, didn't think anything of it until I noticed the bow though. Sorry if that timeline was confusing.

I'm very much thinking I will do a transfer once a $1/gallon sale arrives and run it at <1/2 full until then with my fingers all sorts of crossed.
 
#16 ·
40bs bow a LOT - almost 1/4" of deflection. They are very thin glass. It is unnerving to see them but never heard of one breaking due to the deflection.
 
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