bowing on top of 135 gallon tank

[Little Einstein]

hi guys,
I have had this tank running for about two months now. i have noticed over the past few days that the top of the tank is bowing. it is acrylic. the light is approximately 10" from tank. there aren't any major cracks or anything wrong with it. what am i supposed to do?

thanks in advance and sorry for the bad grammar.

 

[Little Einstein]

here are some pics. the bowing is below the lids.

 

[WeeNe858]

hrmmmm, I have never seen this in an acrylic tank before.....

i would keep an eye on the perimeter of the tank though. Hopefully someone can chime in and help.

good luck!

 

[Little Einstein]

thanks

 

[skjl47]

Hello; That the plexiglass is bowing upward seems odd. I have seen sags and deformation from some sort form of stress. It would seem more likely to sag down from gravity than up. Have the back and sides changed shape? Has some source of heat been close to the top? Let us know if you figure it out.

 

[Jc1119]

My 135 sags down on the top just a bit as the front and sides bow out. I've not seen one bow up either.....interesting. Wish i could help more

 

[twilight zone]

That is a common problem with plexi tanks that is too thin on top. If it was thicker plexi on top, relative to the tank size, it would not happen. I had that happen to my new 180 gallon tank with 1/2" plexi. But, my 100 gallon plexi with 3/8" does not have that problem. The 380 gallon does not have that problem. It is 3/4". I believe the thickness has to do with the relative size of the tank because the water pressure and heat from the water will make a difference.

 

[Little Einstein]

it could be that the stand is uneven. we built it by ourselves. it is level, but the plywood itself may be uneven. Is it a structural problem that i should worry about?

 

[WeeNe858]

If your sides aren't bowing outward then I wouldn't worry about it. Just make sure to check periodically for fractures at the top seam. That should be the highest point of stress.