Rock wall for 72 gal bowfront

I'm going to attempt a diy rock wall. It looks fairly straightforward. But I need advice about a few things. I need a fish safe silicone/glue to ahere my rock wall to the glass. I'm not sure about aquarium silicone because I'm not sure it will stick to the foam. And I need a reef safe epoxy to glue on the sand and small bits. Thanks!