Bioactive Substrate

[Wrath]

I am going to try out the substrate mixture that Philippe de Vosjoli suggests in his book, The Art of Keeping Snakes.

He suggests a mixture of:
peat moss
sand
fir bark
bentonite clay (unscented kitty litter)
lava rock (of the scoria type)

Anyone tried this yet or use any of these substances for substrate? I cant find scoria anywhere around here, only pumice, and I'm wondering if it makes a difference.