I do. I have four bags of it that I throw(two at a time) in the bubble trap of my 75G sump/fug. I also run phosban and carbon in a reactor. I only use it on new systems until the deep sand bed kicks in.
I have some of the bagged - but had bought some of the loose after reading somewhere that it works better in a reactor. But YIKES - I don't want it all over my tank!
Guess I'll just hang on to it until I figure out the best way to use it.
It is a small light weight particle. That is why I use the pre-bagged. Iguess you can buy a bag for it and then put it in a reactor. That would probably work OK.
I use it in a phosban reactor. I put it in between carbon layers. It's problematic in that you have to turn the flow way down and even then there are probably better ways to use it.