See how moist that Rockwool is, that's not good keeps all that moisture against the stem and holds salts.... try ditching that RW and clay and just use A Neo plug and basket pots, you can use 2 inch and cut the bottoms out of the pots for the roots... This will leave you with no excess moisture sitting against your stem and no needless expanded clay..... As soon as I see and roots popping off my clones I put them in 150-200PPM feedings and run up to 300 quick, so nutes should not be a problem if you have roots... That soaked rockwool looks bad and your PH is ten times over crucial when you are in hydro.... Someone commented about how it's easier to fix problems in hydro then soil, correct, but ten times easier to fuck them up to, so Ph being on dial is huge... Alot of these elements are only uptaken at very precise ph numbers and if not correct one can easily lock out another... Now, light from cfl's, ccan be dropped way down as long as you have air running over your canopy, so a foot and a half seems like plenty far away but that all depends on what kind of light your clones were under before you go them