like said above some do some dont
a guy on here has a 750g with no styro
and then every tank i own has styro under it,even a 5g.
why not,it cant hurt to add it is what i say.
i would go with white for 100g or under "never used it but it compresses easier"
and blue for over 100g
i have a 90g and the blue doesnt compress good under it.
but on my 240 it compressed perfect
most home improvement stores have it for say 10 bucks a sheet,8'x4'
sometimes can find smaller pieces