Simple and easy. Turn on the HPS for the normal 12 hour cycle and monitor your temperature in the growspace at approximate canopy level. If you don't have temp spikes over say about 83, you should be okay with most strains. If the temp gradually climbs all day to a max of above 83 or so, you will probably want to vent the light outside. Exhausting it indoors around your growspace will still contribute to high temperatures. Must vent hot air outside. Hope this helps.
irydyum Reviewed by irydyum on . Do I need to vent 400 HPS Cool Tube in a 4'X4' space? I have a 4'x4' area, with 1' section for veg, and a 3'x3' section for bloom roughly. I am going to use cfl's for veg, so heat shouldn't be an issue there. The bloom side will have a 400w HPS in a Cool Tube. Do I need a fan to blow through the tube, and do I need to exhaust the hot air through a vent to the outside. The space gets warm, not hot in the summer, and cooler than the rest of the house in winter. I would apreciate your input and ideas. I am not much of a DIYer. Easy, simple, Rating: 5