I got this from the website posted by Emydura.

http://iwasaki1.sub.jp/24/page.htm

In the center picture they used all pebbles for the potting mix.
I havent tried that before although I can see some advantages in using a mix
like that. (Quick drying, no mix rotting and getting soggy etc...) but I guess you
can do that if you have high humidity.

Very Interesting. It looks like it is working! :D

Looks like chunks of limestone gravel to me like you would use in a driveway.Interesting.

I'm using all pebbles for my B Nodosa and it loves it. Though that's a Nodosa and not a paph :-)

i would think that heavy pebbles would crush the roots of the plants??