Hey i tried to make some Agrocrete using GARF's instructions. I used Portland III cement, and half Florida GeoMarine Crushed Agronite and half crushed oyster shells as the substrate. Using one part cement and 5 parts Agronite, but i had to add more and more cement to get the right consistancy. The bach sits for 24-48 hours then a white vinegar bath for 48. But my cement is like flaking off, i can scratch cement sludge off of the rocks. U think they are safe for my tank? I would really apperciate the feedback if anyone out there has attempted to make their own rocks :lol: :roll: :?: