# Distortion of large acrylic tanks



## larifari (Aug 17, 2011)

Hi,

I have a problem with my acrylic tank, and being in Europe, where (large) acrylic tanks are pretty rare, I thought you might be able to help me.

My tank is nominally 1200 liters/317 US Gallon

length: 98.4 in / 250cm
width: 31.5 in / 80cm
depth: 23.6 in / 60cm with the water rising usually up to 22.5 in

Original Plexiglass from RÃƒÂ¶hm in 25mm/1in thickness

There used to be a small strip of plexi on the top to stabilize the tank. However the seam of this strip broke, and now the tank is heavily(?) distorted.

I'd like to know what is considered heavily distorted and at risk for failure - basically, which grade of distortion on the long side would you consider normal on an near 100 in stretch.

Mine bulges in the middle for 0.6in on one side and 1in on the other (I think the force of the seam rupturing, caused further distortion of the side of the broken seam).
The short side are also marginally bent outwards and the bottom of the tank seems to have risen from the backing for approx. 0.1 in the middle of the tank.

the forum wouldn't let me post a photo, but you can check out a picture at

I'll post the link in a separate post

The picture shows the side with the ripped strip and the 1in bulge.
I removed about one third of the water for safety reasons.

Naturally I contacted the manufacturer, but they still haven't got an idea why this happened (the tank is nearly two years old now). They try to blame it on the substructure (which is still level to floor) and recommend complete replacement, which quite frankly is a nightmare, since we are on the second floor and moved the tank in with a crane while still in construction phase.

I hope you can help me.

Larissa


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## clgkag (Mar 22, 2008)

I think emptying the tank as much as possible to get rid of the distortion and then reglueing the strip that has come loose would be your best option.


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## prov356 (Sep 20, 2006)

Pics would certainly help. But, seams should not come undone if properly joined. If properly joined, the two pieces fuse as one. Acrylic isn't glued, it's welded, solvent welded. The solvent melts the surfaces of the two pieces, then those melted surfaces fuse when they harden and the piece becomes as one. It'd be as likely for it to split open somewhere on a panel as it would for a seam to come apart.

What condition were the seams in when you first got it? A quality seam should look very clear. Think of a solid piece being bent to form a corner. There should be no haziness. A bubble or two or three, as long as small, is fine.

Acyrlic tanks have some give to them and should not come apart or break on an imperfect stand or unlevel surface. These aren't like glass tanks.

To answer your question, some bowing if fine and normal and I think it could take quite a bit without breaking, but very easy to add the brace back for peace of mind and remove any distortion in the view. I can't say where the breaking point would be. An acyrlics shop might be better able to answer that.

Again, pics would help. Add a few posts and you'll eventually be ok to post pics. I think it's 3 or 5 or something like that.


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## BillD (May 17, 2005)

the tank is likely to continue bowing until the problem is rectified. Acrylic tanks are generally built with total top bracing (like Euro bracing), and reinstating the bracing would be imperative. As mentioned above, the joints are welded, with the use of solvent, and if done properly are very strong.


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## larifari (Aug 17, 2011)

Thanks for your answers.

I have a picture of the bend, you can see the strip sticking out over the top of the aquarium










The strip was never really ment to take such a force. It basically was just put in to add support for transport. The aquarium, according to the manufacturer wasnt supposed to distort in this manner. The strip, being only about 2.15in x 0.5in naturally could not take the stress. The seamwas the weakest link, it ripped.

It took several hours for me to find some one to help me emptying the the tank. The distortion didn't progress during that time[/img]


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## clgkag (Mar 22, 2008)

Hopefully if the manufacturer admitted it wasn't supposed to distort that they are going to fix the issue free of charge.


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## prov356 (Sep 20, 2006)

> The strip was never really ment to take such a force. It basically was just put in to add support for transport. The aquarium, according to the manufacturer wasnt supposed to distort in this manner. The strip, being only about 2.15in x 0.5in naturally could not take the stress. The seamwas the weakest link, it ripped.


A few problems with what they're telling you. Tanks need some type of top strips for more that just shipping. Most tanks without some type of 'euro bracing', as it's called, will bow like that, the thicker the acrylic the less it will bow, but it will still bow. It attached by some other means other than solvent welding, then yes, what you see will most certainly happen. So, maybe it was somehow 'glued' for shipping transport only, but then the tank would most certainly bow when filled with water considering the size of the tank and the thickness of the acrylic. They know this, or should if they're in the acrylic tank building business. They're either incredibly inexperienced and naive or are being untruthful. How long have they been building acrylic aquariums? Were they an acrylic fabricator that just branched out into aquariums? Regardless, not a terribly difficult fix and they should be pushed to take care of it. The cost isn't that great to add some proper strips in the proper manner. I know rimless tanks are popular, but I'd not do one out of acrylic and I'd be afraid of doing that with a large tank. You mostly see rimless tanks made of glass in smaller sizes.

If you have no luck with them, I and others here can talk you through correcting it yourself.

Google 'aquarium euro bracing' to see more info on what I'm talking about.


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## BillD (May 17, 2005)

Have to agree with prov356. That tank is ruined and should be replaced by the manufacturer. You might be able to apply a new brace to keep it from getting worse, but I don't think you can ever get that panel flat again. That panel would, at the very least need to be heated, to get it straight again, and that is probably impossible without removing it from the tank.


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## Chunkanese (Feb 4, 2011)

I would say you should contact the manufacturer and ask them to send a repair man, or pay for the repairs needed. This is an issue that can be fixed without a full replacement. The tank can bow without breaking, especially if you drop the water level a bit that will protect it from failing until you get it fixed. Same thing happened to my brothers home made pond. A menonnite built him a plastic pond tank with a cross section in the center. After a few months it failed as the tank had been bowing the entire time because of the way it was designed. Hes still using it, just with half the water until some new cross sections are installed. If the manufacturer wont help you, try contacting an acrylic service company. Plexi is much easier to work with than glass :thumb:


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## prov356 (Sep 20, 2006)

I assumed the pic was taken when it was full of water. Is that so? Did the side straighten out when you drained it?


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