Hi, this is an older discussion from years past:

a link to older discussions:
http://www.thekrib.com/Plants/Fertil...e-jamie.html#0
http://www.wcf.com/pam/pam2scr.pdf

By Jamie Johnson:

http://home.earthlink.net/%7Ekaydeejay/substrates.html

You'll see that Kitty litter is a good substrate based on the data, but ADa AS is very similar and is enriched with ferts, it does not make a mess like Kitty litter also and is more aesthetically pleasing.

You'll also note soil does well.

Regards,
Tom Barr