Hmmm, that's a good point. I wonder how long that would take? If it was a year or two, that would be fine, I get the itch to change things up by then. But if it was within a couple months, then I wouldn't bother. I'd just get another bag of Flourite Black then. Thanks for the tip about Big Als, they're a bit further down the road then the LFS I usually go to, but not too far.
I also found this stuff online at my lfs. Not sure I like the look of it quite as much though, but I can get it in 5lb bags which is nice. I wouldn't need all 7kg of the Flourite.