I personally came to the conclusion we should avoid rockwool like the plague it is. Do you realize how many ten's of thousands of tons of that crap are dumped every year? and gee, it only take several hundred years to break down...
We also need to stop the use it once and throw it away mentality. I've been using the same soil for three years now without a single issue. No, i'm not using it organically, but I could by maintaining a big to let the soil recharge in using organic nutrients and letting it cook. I simply cut out the stump and replant in the hole, and feed the soil nutrients. Because soil retains nutrients better than other mediums, i also use less nutrients, I'm averaging 400 ppms!
ok I'm down from my soapbox lol!