Your clay substrate sounds a lot like Florite.

Reading the blurb, it sounded more like kitty litter to me than Flourite. The
instructions said to put it under a layer of sand.

I know people have had great success with kitty litter type clay substrates,
but I'd be really hesitant to recommend them to a beginner.


Leigh

http://www.fortunecity.com/lavender/halloween/881/