Acrylic cover help

[Bonne46]

So I have to put a cover over my tanks to help 2 issues; 1 being water evaporation and 2 I have a cat who tries to play with the water and fish. So I bought a piece of acrylic called Optimx from lowes. Optimx says it's 20x stronger then glass, and to be honest it is pretty darn strong. Well I've had it on my tanks for sometime now and it has been working great but I'm starting to have a problem. The acrylic is now starting to bow upwards, I have no light on the acrylic, what could be doing this? What can I do to make it not bow? Lastly now that it's bowed how can I fix it, heat it up lightly in the oven?

[Chrisk-K]

A thin acrylic panel is susceptible to bending and it's nearly impossible to get it back to the original state. Buy a glass top.

[Bonne46]

It's actually really thick that's why I was surprised.

[Chrisk-K]

Is it thicker than 3/8"? Then, you probably got a defective one.

[jackiomy]

I just turn mine over when they start to bow. And then back again when they start to bow the opposite way. :)

[RodInCALIFORNIA]

yeah just flip it over

[CWO4GUNNER]

I found out the acrylic properties make it bow as it expands and contracts to temperature and humidity changes on opposite sides unless framed. So even if you were to add a vertical brace along the back like they do on wooden cabinet doors to keep them from bowing, acrylic will still bow from the humidity and heat of the tank on one side and the relatively dry and colder temp on the opposite side, unless you frame it in metal, wood, or glass.

I have to flip mine every week and its getting pretty old after a year now. and seriously considering 1/4 inch window plate cut at my LHS.

[Chrisk-K]

Hmm...I have two Seaclear 40 gallon acrylic tanks. They still look marvelous. But will I be doomed eventually? Well, Seaclear told me that because of their use of special acrylic, their tanks are much less susceptible to bowing. Not sure if it's a marketing gimmick or a fact.

[Chrisk-K]

I found an answer to my own question:-) Most acrylic tanks aimed at the consumer market do bow slightly.

[Bonne46]

Only problem I have is I can't flip it over because I have a notch cut out for the output of my filter.

Guess I'll just go out and buy glass

[CWO4GUNNER]

I ran into the same problem. Originally I had 3 pieces of acrylic that overlapped with the back piece notched. Then when it started bowing I had to eventually abandon the notched piece and use only two rectangular flat sheets that were symmetrical. I have one of those 4" plastic strips they use on the back of tanks for cut outs, they don't warp and you can just leave them in place and never move them.

As for your notched out acrylic you can cut the notches off and use use one of those replacement plastic strips instead for your cut-outs. Then your acrylic will be symmetrical for flipping.