That is a non sequitur. Just make the acyric baths thicker :D
My Biodisk tank for shit digestion is fibreglass and its over 6ft deep.
Perhaps bathing in it would help your understanding of basic structural theory.
I've had some pretty deep acrylic baths..got one due in tommorrow - about
700mm plug-to-overflow IIRC. And 1800 x800.