atm i have soil master select in my tank and its doing GREAT the only problem with this is you have to clean it because its very dusty. just bought 100# for a 75 and 40 this will be along week.
I know they make the two colors, but I've only ever seen the charcoal. My local Lesco only had the charcoal color in stock.
The colors don't make a difference except how you want your tank to look. For me, I chose the soilmaster select based on, among other things, it's charcoal color. It looks good in a tank.