I think you are definitely going to want more air stones, and make sure you have plenty of air moving through them, ie. nothing less than an industrial sized air pump, no Wal Mart fishtank air pumps, etc. You really need to churn the water in bins that big to avoid stagnant areas and rotten roots as a result of the stagnation. As for nutes, not so sure on GH Flora because I use organics. As for the number of plants per bulb, I've found it much easier to grow one big one under one bulb. Good luck! :thumbsup: