ATO reservoir warp?

[Trever]

There are pricey rectangular ATO reservoirs available, but I notice they have lids for refilling and these lids are all acrylic (it seems). My sump is acrylic but the chamber covers are polycarbonate precisely because acrylic covers apparently will warp (from humidity).

I saw one reservoir reviewer complaining about warping. Anyone else experienced this with these reservoirs (Trigger, Eshopps, etc.)? No way I want to waste money on one of those if they have this flaw...

Thanks

 

[Conovan]

could probably email the companies to find out if they are acrylic. I can say my home made 1/4" acrylic res cover warps. I turn it every time I fill it to compensate.