Mate... Its still bothers me that so many people are in love with Crapwool, like bam-bam says not all rockwall it fit to grow in and alot of it carry's big health warnings....
Root Riot cubes are a much better option and you can get them from hydro stores or garden centers... 100 times better than that sloppy mess you get from Crapwool... Just my opinion....
Wow never knew this! Ive never used rockwool my self, but will bear this is in mind for the future!