That is the same mix as seagel either way , I find it tends to separate it's self out anyway , I have set up in D-D reactor in this order bottom to top
Sponge | seagel | sponge (with the top sponge pushed down on top of the media to stop it tumbling)
Which within a few hours it sorts it's self to
Sponge | phosguard | matrix | sponge
I also am thinking it may work out cheaper to mix my own in the long run .