Grates are done, I added pvc legs and raised them high (8") off the bottom so that dc pump with manifold can be installed below the grates, I used 2" pvc reducer that reduces to 3/4" pvc, so i have used 3/4" pvc pipes so that I don't block the flow to sweep under the grates, I put the rock on the grates and i used small to medium pieces of rock and tonga branches to bridge the gap between the grates, I am very happy with the outcome, I kept flat shelves on the front, might want to use for frags on the front and easy access, I am left with 20" x 68" space on the front to grow macro algae and 12" x 68" space on the side for dc pumps to be mounted to blow detritus from the bottom of the sump, I have kept the grates to the other side of the sump where most of my equipment is going to sit. not sure how many pounds of rock i have in the sump but I still have pile of rock left that I can use in frag tank set up and fish quarantine sump... here are some of the pictures