One day I will grow a pair n try hydro lol. I've looked after a mates crop which was done with flood and drain tables and wasnt too hard :/. Keep the ec in the resiviour or however it's spelt right and have the trays flooded with by a timer on the pump. As it runs back into the resiviour you'd have to check the ec and add the right amount of nutes to bring it back up as I'm guessing the plants take what they need. Sound about right? Was ages ago I done it but the plants did manage to live lol