30g tank bowing down the center of the glass? Pics attached!

[Lollum96]

Hey guys, just picked up a new 30g tank..

Silicone sealed a nice divider inside the tank to install a internal tank filter with a jet lift tube.

Everything was going well until I filled the tank up then pop the divider that I silicone sealed into the tank popped out of place!

I thought that's odd! Then I looked at the front of the tank and noticed it was bowing down the center of the front and back panel!

The middle of the tank on the front and back is bowing out (bending) 1.5cm more than the width of the tank.

I know that it's normal for tanks that don't have a center brace to bow a little. But 1.5cm? Is this safe and do you think the tank glass can handle this long term?







Side of tank



Middle of tank!!

 

[LukeOscar]

if it came with a brace it needs a brace. some tanks from the middle era had a metal strap style brace that was molded to fit over the plastic trim. newer tanks generally have it molded into the plastic trim all once piece.

 

[Lollum96]

if it came with a brace it needs a brace. some tanks from the middle era had a metal strap style brace that was molded to fit over the plastic trim. newer tanks generally have it molded into the plastic trim all once piece.

I bought the tank second hand and it didn't come with a brace. Not sure if it should have though!

 

[LukeOscar]

I bought the tank second hand and it didn't come with a brace. Not sure if it should have though!

possible it had the metal style i mentioned and its missing. or perhaps the old owner broke the trim and ordered a braceless trim when it should have been a braced trim. it looks like you have about 3/8s of bowing per panel. thats pretty extreme for glass.

 

[FJB]

It seems as if the force causing it to bow in the middle is stronger than the adhesive strength of the silicone to the glass, particularly since it is applied to a very narrow surface (thickness of the glass).
I had a similar problem with a used 6-foot acrylic tank that somebody had messed up (enlarged the top opening in one side, causing it to bow dangerously).
My solution used a piece of thick plexiglass I had around, which had been heat-bent to a 90 degree angle on one side. I cut a piece and created a 90 degree on the other end, by gluing (weld-on) horizontally-laid small cutouts of plexiglass. I could have attempted to heat-bend the other side, but I glued pieces instead (easier).

I think you can do the same with glass, but the pieces must be placed flat-surface-to-flat surface (not on edge), and using silicone. It is not pretty but not too ugly and it has worked well for me (holding strong after ~2 years). I like it better than metal, which also would work but it either rusts, or releases undesirable ions. Wood is another option but I would use a single piece of hardwood with a properly sized cut-out (not gluing or screwing).
Plexiglass may also work for you; I have never heat-bend plexiglass but I understand it is not difficult if using thick plexiglass.
Photos - the original piece, minus my cutout; the aquarium with its "strap" in place (black circle).
Good luck!

 

[Backfromthedead]

Glass tank should not bow at all. Acrylic can bow and be fine. If a glass tank is bowing then one day it will eventually give way to the stress and the glass will crack or more likely the bowing will actually cause the corner seams to peel apart and leak there.

With a smaller tank like 30g this isnt a huge safety issue imo but could be quite a mess and plenty of property damage.

Long story short, i would only use the tank for a partially full setup like sump or paludarium, use it only in a garage or unifinished basement, or i would fix the tank with a new brace. If its a 30g standard size i believe you should be able to find a replacement brace for a reasonable price online. Or hell, maybe find another slightly used 30g aquarium on craigslist for next to nothing...

 

[Lollum96]

Thanks for all the responses guys. Not going to lie I gone with a very quick and cheap fix which seems to be working. At least for now.

I gone with a 12 inch clamp which I believe is rated for around 63kg. Put the clamp straight down the middle of the tank between the front and back panels. Working very well!

Wouldn't recommend this for large tanks!

 

[jjohnwm]

That'll work, but, wow...looks like hell. I wouldn't want that to be my permanent solution. Great for a temporary quick fix.

Another possible solution, more work to install but hopefully much nicer, would be to make a DIY Euro-brace type of arrangement on front and back. A couple strips of perhaps 3/8-inch thick glass, cut to fit snugly inside the top of the tank and then securely siliconed in place all along the front and rear top inside edges and also at the ends, would reinforce this nicely. This would absolute require that the glass edges and surface being siliconed are cleaned spotlessly clean; absolutely no old silicone allowed to remain. It might also involve removing the top trim in order to properly clean these areas or even simply to get the brace pieces installed. The only issue with this is the interference if you want to use a HOB filter; it would need to be on the end rather than on the back.

I worked for a local all-glass tank builder back in the late 1970's and it is amazing to me how far the makers of tanks today have gone in the interests of cheaper builds; the glass thickness used nowadays is laughably undersized by those bygone standards. Standard 108-gallon tanks back then, 72 x 18 x 18 inches, were built without any crossbraces whatsoever, and none was needed. I forget the thickness of glass we used but bowing simply did not occur to any noticeable degree. The only tanks that had crossbraces were 72-inch and longer ones that were at least 24 or more inches tall.

Those thick glass tanks were heavy...but they were tough and durable as well. Not only does the thicker glass increase strength and rigidity, but the greatly increased contact area for silicone adhesion where a thicker panel is butted up against an adjacent panel was far stronger as well.

I'm sure we are now heading towards a return of frame-built aquariums; they'll just put together a framework and then stretch Saran Wrap around it and call it an aquarium.