i didnt read the replies but....lol
i use styro on all my tanks,why not?
i even have it under my 3g LOL
i can tell you this
im so happy i used styro on my glass 240g
240g,8 feet long
when re setting it up
the ends were sitting on the styro
in the middle,was a large gap
without styro,it would be just "floating" in the middle and thats just
so as i filled the tank
1/4 way,still same gap in center
half way full,i say,gotta sink now,center gap still the same
then at about 3/4 full it sank a bit
then just as it topped off,bam,the center touched styro

now without styro i would be scared the center would have failed cus it was just "floating"
but with styro it sank at the ends and touched in the center
also
you guys think your stands are strait when you build them
check up on them after a few years of water dripping on them and water sitting between the tank and stand,or bad choice of wood "mdf or particle board" LOL
so my opinion is styro cant hurt.....
but then
my gramps used shag carpet between his tanks so......