start lowish say about ec 0.6 then up it to about 0.8 at flower, i never intentionally go above ec 1.0 in bubblers, and have pulled 400 grams off 6 plants under a 400 hps. if i go higher say to ec 1.2 my strain shows nute burn, it is an efficient strain with massive root systems so i dont need lots of feed, also there is a lot of bollocks talked about fancy nutes. you can get away with one product all the way through, just increase the ec slightly at flowering, growth technology products are good they are buffered so the ph dosnt go all over the place, they are also single pack so you dont have to mess about with a and b mixes, and contain a chemical (Nipacide) which helps stop root rot. ive used their Formulex at an ec of 0.650 all the way through and had results as good as anything else. keep it simple and you will have less problems.