Yes. 80 - 90 bucks for 20L is a good deal. I got my matrix from BigAls. Typically, it was just under 30 buck for 4L, so, the deal you make reference to is even better than what I got. Regardless, alot of people swear by Matrix. I can't weigh in personally, yet, because I haven't been running it long enough yet, but as of now, I have totally replaced "all" of my media with Matrix and a smattering of de-nitrate. I don't have any regrets as of yet.