A Few Questions, It's Been Awhile.

Ok so I just ordered a 400 Watt HPS and i was wondering how far away from the plants should the HPS be?
I used to use CFLS for most of my grows,and then 150 Watt HPS for one of them,but i just want to know info on the 400 Watt right now,any help would be appreciated Thank you

With adequate cooling, a 400w can be as close as 10" away from the plant tops. Depending on their growth rate, setting them at 12-13" away each day should give them enough room for vertical growth between adjustments.

edit: This means the distance between the bulb and the plants, not the lamp glass & the plants. It also refers to a stationary lamp. A shorter distance can be used with a light mover.

I've had my 400w as close as 6" with a fan blowing right over it, but I find my optimal distance (# of plants vs light spread) to be 12" from the tops.

I'm currently using cfls for vegging, and 12" is too close when your plants go from CFL to HID. I keep my 400w cfl board 6" from the tops and when I put them into flower under 400w HPS they actually burn at 12". Now I just raise my HPS all the way up on day one of flower and by day 3 I've got it back down to 12".

Also, don't know if you care, but you can make an excellent HID light hanger out of a $4 window blind from home depot. Just buy the smallest one they have (18" I think?) and cut the strings that support the slats, leaving just the 2 strings that raise it up and down. Gut out the crap and cut the top support as small as you can for stability when you mount it. The catch is tricky on these cheap blinds, so use the small plastic slides on the strings as a backup in case the catch fails (I've been using mine for a year and hasn't happened yet, just gotta catch it right)

thanks for the info,will maybe pick up one of those window blinds haha.