I have always preferred a black, or near black substrate, and have used black blasting grit for that reason. But, grit for blasting is sharp edged, and tends to injure Corys mouths, let alone what it does to your hands as you wash it and plant in it. A few months ago I heard of Soilmaster, which is a material made for baseball diamonds etc. They make a Charcoal color version, have a website that allows you to order it online, for pickup at your local dealer, with no freight charge. So, I ordered a 50 pound bag of the Charcoal color, for about $17, which includes California sales tax.
My Soilmaster Charcoal arrived at the dealer today and I picked it up a couple of hours ago. To show off a bit, I took some pictures of a sample of the stuff. They are:
The first photo, obviously, is the bag.
The second is a big handfull of the stuff as it comes out of the bag, dry.
The third is with a couple of cups of water added and sloshed around to clean it. Notice it is dirty, without question.
The fourth is after three washings, and with more water added to show the color. Three washings was enough to get it clean, about what I am used to with blasting grit.
The last shows the particle size and uniformity. Notice that there is some red colored material mixed in, less than 1% I would guess.
The actual color, wet, is pretty black, with sparkles of red. I think I am in love!!