240gal failed, need input....

aquaknight

aquaknight

Active Member
Earlier last week, the left brace on my 240gal let go. I walked out to the tank and found the corner of the halide fixture in the water, and the front pane deflected over 2". How it didn't fail, I have no idea. I immediately drained the tank about half way (having extra rubbermaids on hand saved my bacon). The tank has since been stabilized. I've added the skimmer from the sump directly into the tank, and doing daily WC's. Not a ton of room, but with only 5 fish (granted some are large) in a half-filled 240, they should be fine.
 
My concern here is why the tank broke. I did buy the tank used. The story from the guy was that during one of his moves, the moving company accidentally rolled the tank onto something and broke both braces. The moving companies insurance paid for a new larger tank, and picking my tank up from him, he sure did have a larger tank setup, and he seemed generally like a good guy.
 
I ordered the braces from a local company, 3/8" thick and 15" wide. There are also two 3"-4" braces on the sides of the tank that were there, that I did not touch. I used GE/Momentive RTV103 on the new braces. The silicone that comes highly recommended via another message board. The tank was running for 4 months, then I moved a bit under 3 months ago. Moving a 250lb tank and a 350lb stand wasn't the easiest thing in the world, but I believe we didn't put any more undesired stress on the tank, then one would normally see during a move.
 
 
 
 
The issues that could have caused it.
 
The stand. We built the stand ourselves over the course of a few months. Like to think we did a good job. Checked and everything seemed good, we used a long piece of square aluminum tubing to verify, and the stand was generally flat. Could see some light shining through, but nothing what I would think is out of spec.
 
The level. The tank didn't sit exactly level. Over the 24" gap, the back sits 1.35mm lower then the front. Again, not ideal, but I think that's in spec?
 
The tank is itself. Maybe the guy did lie? It was a previously busted tank I patched back together. Although, it wouldn't think it would have lasted at all this way. Or maybe the move twisted the tank?
 
The braces. Is 36" of support, 30" of real support, not enough for a 8' foot tank?
 
My brace job. Not to influence anyone's own decision, but this I want I keep coming back too. I forget the exactly numbers, but for now lets just roll with it. I ordered the braces 23 5/8th long. When I picked that up, got home and measured, they were more like 23 15/16th. They just squeezed in, but won't slide into their correct positions in the tank. So we took a flap sanding disc on the angle-grinder to them to shorten them up. We marked the glass and made sure were still square. However even after that, they were still 'a little tight.' The braces sit on top of a small nub of glass. Here's a diagram of why I think it was this.
 

 
My theory is that I just didn't get enough silicone inbetween the two panes. That's there the strength from a perpendicular joint of two glass panes comes from. I only got silicone on the top of the brace, and on the under side. Anyone else agree?
 
acrylic51

acrylic51

Active Member
Hey AquaKnight that sucks!!!!! First question is who originally built the tank? What is the thickness of the original panels?
I would assume that the tank is at least 1/2" thick glass or should be. The cross bracing should be of the same thickness as well. Looking at your picture, I don't see how that is giving any support. From my own 240 the eurobracing actually sits on top of the panels not between. Maybe I'm reading the pic wrong. Is the tank eurobraced or just cross braced? My 240 has 4" eurobracing and no cross bracing at all.
I would suspect the stand could play a major factor in failure. Did you put syrofoam down before placing the tank in place? Have you taken a level to the stand befor the tank went in? How is the levelness of the stand now? Did you use pressure treated lumber anywhere?
 
aquaknight

aquaknight

Active Member
I am unsure of the manufacture, no stickers left. Had to guess, I'd say it looks like an Oceanic? The tank has a full plastic rim, so really can't have a brace 'on top' of the panes. Yea, the glass is 1/2" thick, and the braces are 3/8" thick. There are two braces on the sides of the tank. I guess you could say half euro-braced (not really), and then the two main braces. Yea, those braces sit inside the tank. Those little nubs of glass, I guess are there to hold the braces up as they dry?
 
This isn't my tank, but is constructed virtually the same (mine has two center braces instead of one). You can also see the little nub under the right side of the center brace.
 

 
 
We did take the level of the stand at the old house before the tank went in and it was level. Did not measure after the move, but did measure the level of the top of the tank. The tank isn't exactly level, it's leaning forward ever so slightly. Over the 24" gap, the back is 1.5mm higher then the front (using a caliper and level). Though, that's on top of the plastic trim, so dunno if that trim is completely flat on there.
 
There is no Styrofoam under the tank, and we did not use pressure treated wood.
 
acrylic51

acrylic51

Active Member
Hmmm I would have placed foam under the tank to take out any imperfections in the top of the stand. Honestly I don't like/think th tank is/was braced correctly. A lot of people bad mouth GlassCages, and they would no way buil like that. IMHO the tank is under braced for the mere simple fact there isn't a whole lot for the glass crossbraces to bite/stick too. I understand impossible with plastic trim on top.... With the stand being out a bit an my view weak/lack cross support caused a failure. If you look at some of the tanks being built today with litle crossbracing; panel thickness is thicker than 1/2.
I think if you look over on RC there was/is a similar thread with same type of failure. Again it could be a poor seem on the side of the tank allowing the deflection to start, but wouldn't blame the stand. I'll see if I can find the thread over there!!!!!
 
aquaknight

aquaknight

Active Member
Yea, I think I'm writing off the stand, because of how it failed. Tanks that fail because they're not level, or on a twisted stand, usually blow out their side seams or crack a front/rear/side/bottom pane. My Dad has told me stories of back when he worked at a commercial aquarium service, they had a 450gal arcylic let go. They were test filling it on the floor, I guess the floor was way off level. He said that thing squealed, whistled, and howled before front panel tore away and cracked.
 
What I'm not sure will be easy, is if it's underbraced, or was my glue job. I mean, after the left brace failed, both the left corner tank seam, and the right brace were still in fact holding. Granted time would have prevailed if I didn't take action, but once that left brace let go, most of the force that brace was under, had to have been shifted somewhat to right brace, which never failed. Right?
If the brace was a little shorter, I would have been able to get more silicone inbetween the brace and tank, and it would have been a stronger bond. In theory....
 
acrylic51

acrylic51

Active Member
I would be weary of the right brace an really critical of the left seam. Did you already silicone everything back into place? Did u take any measurements on the tank without water and as you fill it? You would easily start to see any mini deflection in the tank itself.
 
aquaknight

aquaknight

Active Member
Oh, no no... The tank itself is done for. There are some spots on the left corner seam that are light from where that part of the silicone lifted. I plan on replacing the tank, selling this one was a reptile tank.
 

 
I was just mentioning how the one brace let go, but the other brace was strong enough (granted for a short period of time) to hold the entire tank together. Right now the tank is sitting half-full, with the skimmer in the tank. Don't really have a tank that would work for a 9" Crosshatch during the interim till I get a new tank. Funny enough you mention glasscages, they are looking like the most likely option.
 
 
scsinet

scsinet

Active Member
I seriously doubt the stand is your problem.
 
The biggest killer of a tank as it relates to a stand is torsion stress, caused by unflatness or leveling issues that present diagonally. It sounds like you were off from one side to another, but consistently. 1.35mm across 24 inches, if my math is correct, amounts to 0.22% out of level, which IMO is well within safe ranges. As a comparison, my 180g is 1/8" off level from front to back, across 24 inches, or 0.52% off, and this tank has been running for 3 years with no issues. I frequently inspect, rechecking level and looking at joints, doing the "dollar bill test" between the tank and stand, etc and have noted nothing that would indicate anything of concern. The deviation is consistent across the whole width so I have zero torsion though.
 
Of course, one could argue that I'll say that right until the day it fails.
 
I agree with Shawn, this sounds entirely like a brace failure to me. Oceanic is the one who did this type of bracing on it's tanks. Oceanic took a nose dive in quality a few years back when they were aquired by AGA (I think... if memory serves), but the glass braced tanks were top notch and are highly sought after. However, read between the lines in what I am saying and you'll pick up that the type of bracing provides insight as to it's age.
 
Here's my opinion... silicon degrades when it is wetted and dried, and the heat from lighting systems doesn't help it either. IMO, the relatively weak silicon joints with the brace butt-ended into the walls of the tank degraded over time due to the fact that they are not submerged, possibly aggravated by long term storage after use at some point in it's life without being re-siliconed. The pressure eventually built up and popped the seam.
 
If it were me, I'd drain the tank, reseal it (entirely), rework the center brace to provide more strength, and put it back into service.
 
2quills

2quills

Well-Known Member
Wow, man...sorry to hear that. Sounds like you got pretty lucky though that the tank didn't completely fail. I agree in the notion that an unlevel or imperfections in the support of a stand could cause a failure but in my mind that wouldn't seem the case in the way that your support let go like that. Did you do anything to prep the glass before you siliconed the supports in? What about the bottom of the supports on the inside of the tank along where the little nub supports are, did you silicone along that area of the joint as well? I would also have to assume that the design of the supports are inadequate as Shawn mentioned...It just doesnt seem to me that this perticular design would be half as good as euro bracing. So I'm a little bit suspect of not only the design of the braces but the fact that you could have gotten an already compromised tank to begin with.
 
aquaknight

aquaknight

Active Member
Quote:
Originally Posted by SCSInet http:///forum/thread/380492/240gal-failed-need-input#post_3311695
Here's my opinion... silicon degrades when it is wetted and dried, and the heat from lighting systems doesn't help it either. IMO, the relatively weak silicon joints with the brace butt-ended into the walls of the tank degraded over time due to the fact that they are not submerged, possibly aggravated by long term storage after use at some point in it's life without being re-siliconed. The pressure eventually built up and popped the seam.
 
If it were me, I'd drain the tank, reseal it (entirely), rework the center brace to provide more strength, and put it back into service.
Only thing is that the braces were new, I installed them myself. The 'old silicone theory' could have effected the corner tank seams, possibly putting higher then normal force on the braces, which I believe acrylic's mentioned. That could also point to two other sources, bad silicone, or a bad install job. I used GE RTV103, what's said to be the strongest/best stuff out there for aquarium use, and it seemed like a good bottle to me. I'll describe the brace install below.
 
As far going forward, the plan is to just buy a new tank (the tank itself) and just "swap tanks." Part of the main reason of this thread (other then to just find out what actually happened), was to help confirm (or disprove) my theories it wasn't the stand, and if I were to buy a new tank, this wouldn't happen again.
 
Quote:
Originally Posted by 2Quills http:///forum/thread/380492/240gal-failed-need-input#post_3311698
Did you do anything to prep the glass before you siliconed the supports in? What about the bottom of the supports on the inside of the tank along where the little nub supports are, did you silicone along that area of the joint as well?
I prepped the brace area. There was some old silicone and crud still here, razored that out, cleaned with alcohol. I did not remove those support nubs. The braces did arrive a little big, and we sanding them down a touch. We would double sure they were still square though. They seemed solidly in place (and still do, they didn't fail with the brace), and I doubted I could remove them without breaking them, and was unsure of how hard getting glass cut that small would have been.
 
Installing the braces, I laid down a bead of silicone and slid the braces in. Cleaned the excess off, then applied silicone to the topside of the brace, and then the underside (brace to nub area).
 
acrylic51

acrylic51

Active Member

 
Kind of hard to tell from this pic, and since I can't seem to locate my pics on my 240 build to show the eurobracing, and even how I had the bracing drilled in the corners....It just appears the support isn't truely there to handle the pressure due to the length of the panel. You can see on the build of this tank the redundancy as to how all the pieces are literally tied together....Overbuilt???? Probably so weighed a ton, but never any doubt it would withstand...
 
As SCSInet pointed out more maybe a silicone issue degrading over time. I did have an Oceanic 150 come apart on me and I bought the tank new and had it only 2 months.....Go figure!!!!
 
acrylic51

acrylic51

Active Member
I used them for my 240 build that I can't find on here, and yes that tank was for an install job that I posted a pic of.
 
acrylic51

acrylic51

Active Member
 
Quote:
Originally Posted by acrylic51 http:///forum/thread/380492/240gal-failed-need-input#post_3311772

 
Kind of hard to tell from this pic, and since I can't seem to locate my pics on my 240 build to show the eurobracing, and even how I had the bracing drilled in the corners....It just appears the support isn't truely there to handle the pressure due to the length of the panel. You can see on the build of this tank the redundancy as to how all the pieces are literally tied together....Overbuilt???? Probably so weighed a ton, but never any doubt it would withstand...
 
As SCSInet pointed out more maybe a silicone issue degrading over time. I did have an Oceanic 150 come apart on me and I bought the tank new and had it only 2 months.....Go figure!!!!
You can see in the pics that it does on this tank have the cross bracing, but on my 240 the eurobracing is extra wide to eliminate the bracing across the tank. I did that to avoid having issues with my MH mounting......They used 1/2" glass for the tank build and all the eurobracing and cross bracing is 1/2" material as well, and you can see it's doubled up in the braces, and overlaps tying everything together. I like to use building with acrylic as an example. When you eurobrace a sump or tank....you don't brace from inside the the main panels. The top bracing goes on top of the main panels. That is where you get your structural support. That is why I don't agree with that little thin strip that the cross bracing ties to......
 
When I had them drill my eurobracing in the corners to mount my OM revs....that was another reason it had to be widened to carry the stress load. Another factor in spreading the load, is that squared off corners don't carry the load as well as radius curves. Very hard to do in glass and you probably wouldn't see it though....But again I revert back to quality built acrylic tanks and sumps....All their bracing is done with radius cuts, never squared if a quality builder does it. It carries or spreads the load better, reduces stress points.
 
 
acrylic51

acrylic51

Active Member
Yeah...the great upgrade!!!!! I have them somewhere on my computer just nothing is organized.....I don't understand why all the pics couldn't have been moved over as well?
 
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