I don't give a fuck about your english...and ... prick or not, you've still given sound advice and the plants can prove it. Thanks again.

no, the leaves aren't yellowing, just the few that are closest to the bottom, its just the hps light on the rest. There is about 1 cm between the top of the hydroton and the lowest set of leaves, and about 2 cm between each new growth on the main stem, is this normal? They seem really compact.

For watering, I'm using a timer with 15min increments, so i have to increase it to 30 mins, is this ok? ppm is at about 1000. ph is rising higher and more frequently with stronger nutes, but I try to adjust it to 5.5-6.0 at least 2 times a day. I just changed this tank of water on sunday and it got cloudy by monday afternoon, smelled bad again.