HPS question

Discussion in 'Growing Marijuana Indoors' started by thepreciouslamb, Aug 11, 2011.

  1. Not sure if this is in the right forum, but I have a few questions about my 400w hps setup: I have a 400w hps w/ that cool tube (glass cylinder around the bulb, w/ a reflector inside the top of it). Does glass filter out UV rays or other absorb any light? Also, Should I use a standard 400w hps bulb, or use ones that are labeled "full spectrum, or "plant growing light"? I use the hps to flower, not to veg, starting next grow lol
  2. opinions will vary but lots of people flower with hps with a little blue in it so i would suggest full spectrum
  3. Thanks man. Do you know if the glass from the Cool-tube blocks out the UVA/B light? Also, how would you suggest I add extra blue light?
  4. Full spectrum bulbs have both blue and red light I think sometimes there called dual arc bulbs
  5. The cool tube will absorb a little of the light, but you should be able to keep the light closer so you will more than gain back any light intensity lost to the glass.
  6. Thanks for the info. I have some dryer duct going from the end of the cool tube, & out the grow closet. I keep the light about 5" from the plant tops, it never gets above 80f. I like to keep the plants short & bushy until I start flowering, then let them grow taller. They get tons of nodes & densely packed bud sites

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