Cracked bottom trim/frame

R

Reef Dude

New member
Yesterday, I noticed that the bottom plastic trim piece on my tank is cracking at 2 corners. The 2 corners are on the same end of the tank, and this is a 180 gallon glass tank measuring 6'x2'x2'.

I looked at FAQ's on the manufacturer's (marineland) webite. This question is asked a few different times, and Marineland has a different answer everytime the question is asked. Answers range from this situation not being a problem because the bottom brace/trim piece provides minimal support because the glass bottom holds the bottom part of the tank together to answers from Marineland saying that it should be replaced.

This tank is full of water, fully stocked with fish and corals, and has been in place for 3 years. Has this ever happened to you? Is this cracking a concern? I'm not tearing the tank down to replace the bottom plastic trim piece... I'd rather just by a new tank altogether and it would give me an excuse to upgrade!

The tank is out of level 1/4" from left to right. The lower end where the water level is higher is where the 2 bottome frame corners are cracking. Coincidence? I didn't think 1/4 inch was to big of a deal over the span of 6', but maybe I'm wrong. It sits on hardwood floors, and it seems impossible to get a shim underneath. The top frame has no cracks and looks good. I notice no obvious bowing of the glass.

So, is the bottom frame structurally significant? Has this happened to anyone, and what did you do? The cracks are not the whole way through the frame yet, and the one is just starting. Also, with 2000+ pounds here, how do I get a shim underneath. The wood shims (narrower "point") break when I try to shim, and the composite shim points are too thick to get a shim started. I'm trying to avoid draining the tank since it will leave all my corals out of the water, and it would break apart all the larger coral colonies growing across multiple rocks and the glass if I remove the livestock. Any advice or first hand experience would be greatly appreciated.
 
Yes the bottom frame is structurally significant. Tanks without rims are engineered differently than tanks with frames. A broken frame is not doing ITS (for sleepydoc ;) ) job any longer, and needs to be replaced.

Since Marineland is not Marineland anymore, rather a small part of a large conglomerate, you are likely to get as many different answers as the number of times you ask the question. Some folks you talk to know, some don't. (Same with the tempered glass inquiry.) Unfortunately, since Marineland tanks have been counterfeited, the replacement frames are no longer available, and the incidence of Marineland tank failure has been on the rise.

Since your tank is showing signs of pressure induced failure, (due to the pressure exceeding the engineering specs by being out of level; the reason why they require a particular stand to maintain the warranty) the next step in the failure process is a full blow out of the seams.

At any rate, in order to perform any mitigating repairs, the tank is going to have to be drained to halt the failure process, and then leveled using shims under the stand. Then the tank needs to be inspected by a professional with experience in tank construction and repair, (not a local fish store, or a friend that built a couple of tanks, or even a glass shop,) to determine what will be needed to restore the tank's safety. I have the experience, but I am not so bold to think I can give you an answer from your description, or by looking at a photo. All I can say is the tank is headed toward a failure, I would have drained the tank yesterday, and someone with experience needs to get their hands on it. You sorta have to bite the bullet. It is going to be a nightmare to take the tank down, but it will be a bigger nightmare if a seam blows, you loose everything, and damage your residence.
 
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Thanks for taking the time to give me a detailed response. I was expecting something along the lines of what you mentioned, but I was hoping that wouldn't be the case. I'm shimming it to get it perfectly level right now. I figured that shimming can't hurt. The cracks are pretty small, and they do not go the entire way throught the trim piece, so there is still some structural integrity there. Definitely a sign of being over stressed though. Probably just going to buy a new tank entirely, although I might see if leveling it helps prevent further signs of stress and then monitor for a little while. I've had several tanks previously, and honestly, some were more out of level than this, and I never saw signs of stress. However, this is the longest tank I've owned, so maybe these longer tanks are more sensitive to these effects.

Thanks again.
 
As an update, I called Marineland directly to discuss this. The person I spoke with told me that the bottom plastic frame offers no structural significance whatsoever and that the trim is on the bottom of the tank to make it look "pretty". They told me that the top frame, specifically the top braces, are the important structural pieces. I feel like that answer is crazy, and I thought I would share in case anyone else is having this same issue. I could see them saying that a small crack doesn't effect the overall integrity of the bottom trim or that the bottom brace/trim offer minimum support, but to make a blanket statement that it offers no support to the tank seems insane. The tank does sit inside the frame and is supported by the frame underneath the tank if nothing else. Crazy.

I'm still taking your advice, uncleof6, so don't take this as me finding another answer (one that would make me happier if it were true). I was just shocked by the manufacturer's answer, and she basically lost all credibility with me when she said it is there to "look pretty". My lfs also contacted Marineland recently about this same issue on one of their tanks, and they received the same answer.

Anyone want to test this theory? Take the bottom trim piece off your tank to see if it lasts? Although apparently it wouldn't look as pretty if you take it off. Ha!
 
First off, you unfortunately can't depend on the person you spoke with knowing what they were talking about. They may have the correct information, but it's difficult to say for sure.

I can kind of see what they are saying - the walls at the bottom of the tank are held/supported along their entire length by the structural silicone seal to the bottom panel. In contrast, the top is only supported at the ends without the frame. Whether the support on the bottom without the frame is adequate or not I cannot say.
 
Did you ever resolve this situation? I've been trying to answer for myself whether the plastic trim is structural or not. I realize the top trims that have a center brace are structural, like on a 120, but i really doubt the rest of the trim is anything other than cosmetic. For example, could you take the top trim off of a 40 breeder (no center brace)?
 
Willistein said:
Did you ever resolve this situation? I've been trying to answer for myself whether the plastic trim is structural or not. I realize the top trims that have a center brace are structural, like on a 120, but i really doubt the rest of the trim is anything other than cosmetic. For example, could you take the top trim off of a 40 breeder (no center brace)?
Click to expand...

No, because it is just not that simple.
 
In short, no I never really resolved my issue, and I'm still debating what to do.

I spoke with some of the guys at my lfs, and they said that their Marineland rep was just in to the store, they looked at a couple display tanks with similar cracks, and the Marineland rep said that cracks on the bottom trim are nothing to worry about. In fact, the lfs has some tanks on display with cracks in the bottom frame that they are selling at a discounted price, but they tell me that they are telling customers that it is still ok to fill with water.

I can see how the bottom glass holds the tank together, as it basically acts as one big brace for the bottom of the tank. But I still wonder why the mfg installs the bottom brace if it is not needed structurally. Maybe it is to match the top of the tank so it is aesthetically pleasing? Maybe it makes the manufacturing process easier? If the bottom brace doesn't provide support against bowing of the glass, why does the bottom piece have cross braces?

I wonder why my trim cracked on the corners of the same end of my tank? I could see how it cracks during shipping, but my tank has been setup for a few years and I only recently noticed the cracks.

As you can see, I'm left with more questions than answers. I did shim my tank (under the stand) so that it is perfectly level in all directions now. My gut tells me that the bottom frame is of some importance, as I would never remove it entirely. However, I am not sure how a couple hairline cracks effects the overall integrity. Given my discussions with my lfs, it seems to be a fairly common thing. It seems like more people would be dealing with this issue, but I scoured the internet and found very little information on the bottom trim piece.
 
uncleof6 said:
No, because it is just not that simple.
Click to expand...

I guess I'm looking for more info than just your opinion (no offense). Can you point me to evidence for this statement? I find it hard to believe that the tank manufacturers have done structural analysis on the flimsy plastic rim...
 
Reef Dude

Not apples to apples but I eventually sold my 55 gallon reef due to a cracking center brace, plastic. Was not cracked all the way through but just never had a peace of mind about it.

But here are the apples to apples... Regardless the many answers you have received, it's hard to enjoy the hobby while you're wondering what your house will look like should the tank blow. 55 or 180, it's still a lot of water and money gone.

I think the only thing that will make you feel better is to do the unthinkable - replace the tank with another manufacturers tank.

But that's me and your mileage may vary.

Just my 2 cents and gets you a bump.

Harbour
 
I agree, Harbour. Rather than worry about if or when the tank will blow, I'm thinking I'll just replace the tank at some point sooner rather than later. I look at my tank differently now... I used to enjoy it's beauty. Now I see is a disaster waiting to happen. It's weird... Of all the thing we worry about.... Alk swings, pests, cyano, too many nutrients, too few nutrients, etc. I'm always so focused on maintaining the quality of the water IN the tank. I never gave much thought about the tank itself failing. It's one of those things we take for granted until something goes wrong.
 
The bottom frame does transfer the weight of the tank to the outside edge, thats why the glass is lifted off the stand. All the weight is deferred to the tank frame, then transferred down to the stand. Thats why you see most stands have no upright support in the center area of the tank.

I thing what the manufacture was saying is that as far as the tank blowing out at the bottom, the frames not an issue. Or, horizontal support is not an issue. Because the weight is transferred vertically. If there were pieces of the frame missing, where part of the glass was not being supported between the stand and glass, that would be considered structural.
 
Willistein said:
I guess I'm looking for more info than just your opinion (no offense). Can you point me to evidence for this statement? I find it hard to believe that the tank manufacturers have done structural analysis on the flimsy plastic rim...
Click to expand...

I have been a professional tank builder for 20+ years. It is not an opinion.
The glass is not thick enough for it to be a rimless tank, of this size. Rimless tanks are built with thicker glass than rimmed tanks.
 
Over the last 20 something years I have done more analysis than you would care to think about. I know what holds together, and what should not hold together. Your mileage may vary. You asked a question, I gave you the answer. I am sorry you don't like the answer, because it contradicts what you want to believe. If you want to take the rims off, go ahead, it is not my tank. :)
 
I'm really just trying to understand what the plastic rim does and you're not being helpful. No, you didn't answer my question, and no, you don't know what I want to believe. If you don't want to have a constructive conversation, why do you respond? I don't really care what your resume is. I'm done here, I'll model it myself.
 
Willistein, the plastic trim does one of two things depending on its location. For the top it reduces/minimizes the deflection of the long glass panes. This is especially true with the cross-braces. For the bottom, it externally braces the bottom seam, buttressing the seam against the outward pressure of the water. Again, the cross braces on the bottom transfer the load straight across the bottom of the tank.

Does the very corner of the plastic carry much load? Probably not. At the corners you get the same loads seen in other places but you also have the vertical seam taking some of that load. While it may be fine, I wouldn't trust it long term. My recommendation is either replacing the frames or the tank.
 
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