how many light bulbs should i use for 10 plants in a hydroponic system? should i use 600 w are 1000w and the reflactor should it be aircooled are not?
Definitely use the 1000 watt, or two 600 watters. Using air cooled hoods you can control grow room temperatures a little easier (if you don't have dedicated A/C in there). It can also allow you to get the lights closer to the plants.