well I have 2 autos right now. So how high for it to cover both?. If I lower it to four inches. It wont cover the 2 plants.
Hiya texastiger707 n Happy Holidays. Just my thoughts..but if you have the 150w Hps 4" from the Tops of your Ladies...then you gotta be COOLING the Bulb directly..as well as managing Grow Cupboard/Cabinet Temps...best way to check the Heat when lowering your light(That I've Read) and use is the Hand between the Tops of Ya Ladies and the Bulb..if your hand gets Hot then so are your Ladies...
Now as for the best Light system to use: Hps VS CFL or Both?? a Giant 200w CFL kicks out about 8000-10,000 Lumens(depends on brand) and I Think a 150w Hps kicks out about 16,000 Lumens(depends on brand), but you have to take into account the space you have to grow in? The Air flow and the ventilation of Heat..CLFs work best up close 2-3" and Hps 12" standard? but can be lot lower if the Bulb is Air-Cooled...
Hope this is of some help...
If you have space could use both Hps at Top and CFL closer to the plant.