i use these they work just as good as hydroton and are lighter and bigger chunks so a little easier to work with, and a little less residue to wash off.
wow i totally reuse as much of all my medium ( coco, hydroton, growstones ) as possible. Just shake the roots around in your hand. No reason to waste good medium. Unless you think dumping the old hydroton, driving to the store, carry it to the register, paying for it, loading to your car, driving it home, unloading it, prewashing, etc is easier than reusing...
exporting more money overseas, adding to landfills, draining ur wallet, wasting water,... ;D