Ok,
Don't they make ceramic cloth (it would have to be the lightest weight possible)? And it could wrap all the way around the tank in the critical areas and be stitched together and resined in place. Or maybe it could cover the critical areas and be stitched to a substrate underneath the foam, around the perimeter of a large area, so that if a chunk dislodges it is contained within the much larger "net", so to speak.