I washed some more black diamond "sand" (actually coal slag) and took pictures of each step. I know when I first got some I was wanting pictures to know what to expect. I got one 50 pound bag of the medium grit (20/40). It doesn't feel sharp and my cories do fine in it. It doesn't cut or hurt my skin but it does scratch up my nails. So if you care about that I recommend using a stick or strong wooden spoon. I'm weak so I only filled a 4 gallon bucket a little lower than half way. (The second batch I filled a little over halfway and made a lot more of a mess.) 1) Filled bucket with hot tap water. Didn't even have to stir to get this stuff up. Pouring off the first rinse water. I was pleased at how much the sand clumps together and doesn't readily want to run out of the bucket if you go slowly enough. You don't even have to go painfully slow. 2) Second wash 3) Third wash, dig a little deeper with the spoon and got some more dust up. 4) Fourth wash 5) Fifth wash, I started to be able to see the sand below the water. 6) Sixth wash 7) Seventh wash, just for kicks and science... When I fill the tank with water I do it fairly slowly onto a plate so the water doesn't kick up the sand. My water is pretty clean after an hour. Hope that helps another visual learner like me!