I believe the substrateless incubation involves no direct contact between substrate and eggs, similiar to what Becky has going on... http://www.ball-pythons.net/forums/s...890#post567890

I think the perlite is only used to control sloshing of the water, not as an actual substrate per se.

I have gone with the vermiculite substrate myself, but I've only got the one clutch and seem to be doing great on it.