I think the rockwool IS your problem....and you need someone to tell you what to do with it. I know it's notorious for soaking up and holding water and needs all sorts of special care.....presoaking....careful watering times..gets screwy on the ph....etc etc. As I say, I don't use it so can't help you with it....but I'm sure someone else does and would know what to do. Somewhere around here I posted something about the stuff awhile back....let me check my old posts.