3m colorquartz is heavy because it is an epoxy sealed quartz. The resin coating is non porous and pretty much impervious to almost anything that a normal fish tank can throw at it.
I just got some 45-49 grade white quartz filter sand. It is a decent size and is not getting sucked into my drain lines. I have about 5000 gph flow in there just to see what happens. The colorquartz of similar size is much heavier though.
