400 w. New to the HPS game ??!!??

Freedom Fighter

Well-Known Member
coming from the CFL sub forum. SO i have the undersanding that.. the closer the light the better..

But i just upgraded to a 400 w HPS system. So now...


How far should this light be from the girls when on a 12/12 cycle????
 

jrp677

Active Member
How far should this light be from the girls when on a 12/12 cycle????
My 400 Watt light is air cooled and I am able to keep the tops within 8 inches of the bulb. I use the hand method, put your hand at the same level as the plant tops, if its uncomfortable for your hand then the light is too close.;-)
 

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Green Cross

Well-Known Member
My 400 Watt light is air cooled and I am able to keep the tops within 8 inches of the bulb. I use the hand method, put your hand at the same level as the plant tops, if its uncomfortable for your hand then the light is too close.;-)
without air cooling I'd start @ 18" - especially if the plants are coming from a CFL environment - then gradually move it closer until it's 12" or you see leaf tips burn. Then back it off. Be careful :fire:
 

Freedom Fighter

Well-Known Member
thanks guys. it not air cooled.. nice light Jrp. mines just a bulb and a wide hood so i'm assuming it will get pretty hot. Ill be starting it around 12-16 inches ... but we're in agreement?.. 12 inches is the min distance it should be?
 

jrp677

Active Member
Agreed! 16" would be a good starting place and then work down as far as you can. Good Luck!
 

trouble9039

Well-Known Member
I would start with it at 18" unless air cooled! I have cooked my plant's off A 400 that was not air cooled, so be careful and they will tell you when to stop!
 

Scyntra

Well-Known Member
well I'm probably the minority here but mine is about 8" from the tops not air cooled.. but I have a good AC setup..as others have said use your hand if you would not like your hand that close for 12 hours your plants wont like it much ether..
 
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