I've used the special grade also, but when I replaced the substrate on my 115 gal mixed reef I decided to try Reefflakes. Great stuff, and did not blow around my tank as I feared. Yes it's clean, but I still had to wash it throughly before use, and it took a day to clear up. I bought 3 bags on line at a discount, but really only needed 2. I might add to my 30gal office tank, currently bear bottom.