I am about to start my first deep water culture grow (I have done several grows with soiless mixes) I know how to check and maintain the ph, ppm and temperature levels. What I don't know is what kind of nutrients I should include in the water. Also, the main guy I learned from told me to change out the water once a week, but should it be more often? I heard it's good to let the plants' roots out of the water to dry out a bit (into a empty bucket) for a couple hours here and there. Does this have to be on a set schedule or can I just do that when i have time? I know many deep water culture growers don't do this at all. Any other tips are also welcome. I am mostly going this way because it is cheap, simple, and I've been wanting to experiment with hydroponics.