repaired tank

So I got this huge (to me) tank and sump from my buddy and i have a few questions. This tank was sitting in my buddy's field so as you see it is dirty also some of the seams have busted on the tank sump is intact. My plan right now is to clean up and repair the 100/110 gal tank and set it up...

So ive decided to make a 3d background out of real stones.. should turn out good.. how ever i had a small crack on the side from it having water in it in the garage.. winters up here in canada get a lil chilly.. anyways heres the start.. Started by covering the crack with silicone