Tub bottom bubbled up?

I got a sterilite tub and today I noticed the bottom is bubbled up. The plastic is not melted, but its like the whole bottom has warped evenly up in the middle. Any reasons for this? Heat mat is at 92 degrees and ambient is 80

[QUOTE=pigfat;1718151]I got a sterilite tub and today I noticed the bottom is bubbled up. The plastic is not melted, but its like the whole bottom has warped evenly up in the middle. Any reasons for this? Heat mat is at 92 degrees and ambient is 80[/QUOTE

2 things jumped into my mind really quickly when I read this 1. you had a heat spike and it bubbled your tub 2. you have a defective tub, sometimes the tubs are made defective and they just can't handle ANY heat at all

Agreed with scaleyz

Are you using an on/off t-stat? The on/off types will deliver 100% power while on they can allow the plastic to get very hot and this maybe why you are seeing deformation in the tub.

I would not suspect a faulty plastic run it is possible but not very likely (very carefully controlled) a very thin bottom is more likely that would compound the problem.