Salt brine water softner canister info?

I recently had to empty out everything in my water softner which is a Whirlpool, with salt tank & canister. I also emptied out the canister as it appeared to be stopped up with sand. I had a new deep well put down. The old one was sucking sand. What material can I put back into that canister & how much should I put into it. It has a cone shaped thing at top with a piece of plastic pipe running down to another cone shaped filter on the bottom of the pipe. This is located inside the canister. The material that came out looked like tiny beads dark in color not much larger than the sand itself. Almost a coffee color. I have also cleaned the screen in the head & am soaking all parts in iron-out, except the o rings. Any help as to the material I can put back into the canister would be greatly appreciated. This is a filter for my whole house. The salt brine tank area had been flooding & the unit had not been using the salt up. All the parts were loaded up with sand.