HELP The top of my acrylic tank is separating!

[Shablin]

I need advice on what to do;

my acrylic tank measures 6x2x3ft deep; we moved it about 2 months ago; I noticed today that the top piece of the tank has separated form the front. I am worried that now all the stress will attack the sides; Am I overreacting? I need advice how on the best way to reattach the top - I've never worked glueing (or reglueing) acrylic before. Thanks! I also posted this in the large tank forum

[T Sandman]

Is it full?

[Shablin]

yes its full of water, a lot of rock (which I suppose reduces the pressure by displacing water) and some livestock.
I am going to brace the top untill I can come up with a plan
The sides look perfect

[Zephrant]

Shablin- The rock does not reduce the pressure, it is the depth of the water that matters. Unless you filled the tank part way with concrete, the rock does not make a difference.

We really need some pictures to diagnose the problem- Guaranteed that you will have to at least drop the water level though.

You will also need to determine why it split- Most likely the cause is a stand that is no longer flat. Once it sets for a while, it can settle in.

Please lower the water level before the front panel splits off, and check the stand. Post some pictures and we can give you some hints.

Zeph

[Acrylics]

How long is the separation?
Is it *only* in the seam or has it migrated to the vertical panel?
Can you give some specifics on the tank? material thickness? what sort of bracing/flange is on the front? Trying to figure what we have to work with.
Do you have another tank you can put your animals in "just in case"?
Sometimes tanks can be repaired when full, but generally not.

James

[Shablin]

it will be difficult to see the separation but here goes; It is the top (eurobrace?) that separated from the top of the front. I am going to try and lower the water and install pumps to kepp the circ going (it will be tough to get enough flow for the mag1200 pump)

[Shablin]

Zeph
I know there is a lot of water wieght but if you think of an empty tank filled only with rock, all the force is down - none at the front unless it is stacked against the wall. Liquid wt. sends its force down and also to the container supporting it. (any littlle decrease in wt. helps!) There's probably 700 lb of LR in this reducing the total liquid to about 200 gal-Brian

[Shablin]

I read that Weld-On is a good glue for acrylic. (I also read that glued acrylic is stronger than the acrylic?!) I think I would have a hard time getting it in that space, as well as cleaning the space out. I have no idea how to do this! Do i have to pop the top off? buy a new tank (i like this idea)? Anybody use this stuff before?
Thanks

[Shablin]

The only separation is the top seam. The sides look as good as new. I only have temperary storage in house (ie. trashcans 20 gal aquariums, buckets, styro boxes, sump etc.) The sides are 3/4"; top brace is 1/2"; I might be able to temp store @ LFS but for the volume of stuff this would be a REAL hassle! need any other info?

[Shablin]

PS.
tank is level; has been on this same stand for 5 years! floor it is now on is tile on concrete; I can't detect any obvious imperfections in the floor/flooring - spills don't run - usually remain static (untill my wife mops 'em up). There is some warpage on the top plastic - this has always been there. There is about 30 inches of the seam still attached. about 6 in at left, 12 in at right and 12 inches mid-left

[sabodish]

just a little side note here..there is NO pressure at the top of the tank...pressure distributions start at zero and increase in a triangular distribution until the bottom of the tank is reached..at the bottom, the pressure is 62.4 x Depth..this force acts at 1/3 D up from the bottom of the tank

[Shablin]

I know this isn't fixing my tank, and what you say makes sense to me, but why do all acrylic tanks have a top brace? Just to keep em square and prevent warping? PS. I didn't drain my tank but I did put long c-clamps and 2"x3"x6' along the front and back to help it keep it's shape. The front is only bowed about 1/8th and did not change over the 24 hr since I posted this. The more I read about acrylic, the less optomistic I get that I can fix this without draining it and placing a lot of effort to remove the top, refinish the sufaces and reattach it if possble ( I might need a new top cut as this one is slightly warped). I would appreciate ANY ADVICE OR DIRECTION REGAURDING WORKING WITH ACRYLIC. My present plan is to buy a new, similar size glass tank and then fix this one. Thanks in advance for any suggestions!

[Acrylics]

May sound a little odd but, you stated that you just noticed the separation. It is possible that it has been this way for some time, does there happen to be dried salt or any other particulates in the separated area?

Top braces are to keep them from warping in one respect, but also to use thinner material. A tank with the top brace can be made of much thinner material (for a given stress factor) than a "topless" tank.

IMO a new top ought to be cut and glued on if you wish to try and fix this one. It will take some work, and to be perfectly honest, may not be worth it to try and fix, esp since gettin a new one is your present plan at this point anyway. IMHO, you *may* be better served selling this one as a "project" tank. That is unless you want a "project" tank of your own, then by all means go for it :)

I wish I knew someone well enough in PA that you could go to with this one, I'm sorry I don't.

James

[Shablin]

The separation probably started a while ago; there is dry salt and a very small amount of algae on one side however ther the larger separation is not continuous with this. Thanks for the advice.