I'm seriously considering trying this. But so far I've only found one report
of anyone using it, and am curious if there's any other Haydite users lurking out there.
It's inert, fired and expanded shale. It seems to have a very attractive combination of properties, which really isn't available in any other substrate:
1) Mixed color similar to pea gravel, but a bit darker; a nice natural look.
2) Available in a variety of sizes. I'm looking at 3/16".
3) Weight is more than Turface/Schultz, and close to Flourite.
4) The CEC of the bonsai grade is supposedly better than Flourite, although not as high as Turface.
5) Price seems reasonable. The report quoted $12 per 35lb.
It may be hard to find. But the bonsai shop mentioned in that report is just an hour away from me.