Clay in substrate

Hi all,

I'm responding to the query regarding anyone trying red art clay in their
substrate.  I have used it & have not noticed as favourable plant growth 
as acheived with Dupla laterite.  The Dupla laterite I used did not
cause any noticeable cloudiness for me when I gravel vaccumed (I have
used Duplarit K & G in different tanks).  I molded the art clay in to
balls & let them dry before using it, but after a few days the balls
became pretty mushy & released clouds of "dust" when touched in the
tank.  After gravel vacuuming the cloudiness persisted for almost a
day.  I have tried the art clay in the same tank as I had used some
Dupla balls in & got very different results.