BigBill said: I found them on the web.
Are you aware that the maker of "grow stones" went out of business on January 26th, 2019?
I was not aware. I watch "Ed's Orchids" on Youtube. He uses them in his Phragmipedium mix. I will try to find out what they are. I think they are limestone chips. Don't know, but they are white. They are not for aeration or non-carbon-based media, they are for trace minerals. I am now using rock dust. (Gaia Green) but wonder if it is more basalt than limestone.
