Perlite alternatives

[apacin0]

I've done 100% coco coir before and it works. I used a small pot, I can see it getting more expensive with big pots. Fluffing the coco up with some other medium I think does help with total cost for larger volumes. I think if you're going to reuse your mix, the clay pebbles are the better route.
..Also get some dang new coco lol. The stuff I buy is very fibrous and full, not powdery. Maybe mix that powdery stuff with new coco, if you really want to save it.

 

[Rootsruler]

I wouldn't the powdery silt will collect on the bottom and choke out your roots.