I started out using the general hydo 3 part sysyem, but switched to floro nova. Not near as complicated to use. Seems to be working really well, and plants have just exploded in the last couple of days. I have them on a 20 on and 4 off under a 400w mh in a 2 x 4 area. Also, thamks for all the help from you and the other posters on this forum. You have all saved my plants from harm many times over.