I am getting confused, to say the least about artificial lights themselves and day lenghts.Many books advise a day length sced. like; Nov.-Jan 16/hr.days, Feb.-June 18/hr. days, July-Aug.16/hr days, Sept.-Oct. 12/hr.days. Most agree not on specifics, but that the hours must vary for flowering to occur. I have four G.E High output T-5 fluores. 54W/6500K and 3000K (2 cool white and 2 warm) bulbs that have been on 14 hour days since 9/13/2004.I recently raised the hours to 16 to follow these guidelines,but my phals were already purple though very far from the lights( but blooming , the ones four feet or so from the lights are still green!), and even my catts. seem to be getting a bit too much yellow green, one is yellowing on the tips (it's not from culture, as I work for growers and am well informed about that at least, and they are also rooting like crazy), so I'm not sure upping the hours is a good idea,maybe I should just lower them in the winter.I have a blue vanda in dyna-rok as an experiment under these lights which are 21 inches away from the top of the plant (like the Catts.), with only 50% humidity, and the roots look healthy,plus it's in spike right now! My mini catt also bloomed, but my bigger catts have'nt yet, but are rooting like crazy.Are these bulbs o.k, or too strong? or should I try the Gro-Lux everyone keeps touting? So much for fluorescents being wimpy! I'm getting brain blisters trying to figure out the whole scenario.I do hope that a member makes a site for artificial lighting!