Possible problem: My tank is expanding in the middle!

[tony3]

Is it normal for a 55 gallon acrylic tank to expand in the middle of the tank as you add water. I purchased the tank from someone that used it for 5 years. I have the tank half filled, and the middle has expanded by an inch in the front side. I know that acrylic is a flexible substances, but is it OK to have it expand this much?

 

[BillyZ]

that would worry me considerably. is the center bar in the top frame of the tank still intact? that should be your first place to look!

stop filling the tank until you resolve this. it should not bow at all. I have a 55 acrlyic.

 

[d9hp]

That does not sound good.

 

[reefrunner69]

If it's a thin acrylic, it will expand, it's not so much that the tank is bowing as much as when it is empty it sinks in a little. Acrylic, is flexible and the reason for the lip around the tank, is to prevent bowing. If you think that is scary...you should see it happen with a large glass tank. Is the tank actually bowing, or is it just filling up a it? you should be able to look along the side and see if it's bowing out or not.

 

[tony3]

Here is some more information:

I think the tank may have been like this with no water in it, and it is almost perfectly level. I have put 6 more gallons of water, and it has not expanded anymore. Is it possible that the tank was designed to be slightly bowed in the middle?

 

[tony3]

The center bar looks OK to me, and the acrylic is about 1/4 inch -- is that sub-normal?

 

[BillyZ]

well I think we've found the problem.

How come your center support bar doesn't come all the way across?

 

[d9hp]

I dont know what to say, but it looks like that one rectangle in the back was cut, and did not come cut when the tank was constructed, I could be wrong though.

 

[BillyZ]

(((ignore my post... i'm growing old and my eyes are failing me!!)))

 

[d9hp]

I was thinking the same thing Billy!! I then looked closer to find that the outerlip was lighter and you could not see it.

 

[stresco]

I've only got a 10gal acrilic, but it didng bow at all when i filled it. That would really concern me. I'd hate to get a phone call from my downstairs nieghbor telling me its raining in his apartment.

 

[d9hp]

O trust me, my house has flooded and it is terrible. We opened the garage door and NIAGRA FALLS! Turns out the washer hose burst. Dont forget to change them every year ok guys? I was out of my house for over 2 months and the damage was over 20 grand.

 

[tony3]

Quick Update: The tank is full now and it still has 1/2 to 1 inch bow in the middle... but I checked several other 55 gallon acrilic tanks... and they all have a slight bow in the middle (you need a yard stick to see it usually).