no the styrofoam will be under .5-1" of gravel and it will not melt/release toxins since people use styrofoam in diy backgrounds without problemsstill. . . they won't dig or anything? and like the styrofoam won't melt and release toxins into the tank?
hardest part was actually trying to find the right place for each piece.. everything else was pretty simpleLooks like way too much work too me.
My parents live in the middle of nowhere in Nevada and they have tons of slate around them. They just used it to rebuild there fireplace and had some sitting in their garage. So when they invited themselves to my place for Christmas, I made them bring me 50lbs of slate. I broke it up and stacked it in my 125. My koi (that have a home in a pond in the spring) have been rearranging it to their desires. Kind of looks like a natural rock-pile now. I'm thinking of renting the koi out as decorators.