I have used it but in small quantities over time, changing frequently. It never worked the best for me compared to gfo. My purpose for it was silicate, and for that, it worked well.
For phosphates, it's OK, but in my use, gfo is better and more forgiving. I never had a problem with my softs or stones btw.
If you decide to go with it, just rinse it really well in di water and don't fluidize it..
Sent from Note 2 on Tap 4