# 2-400w HPS



## red_ss (Mar 4, 2008)

i just got a new 400w hps+ the one i have so now both is 800w.. whats the distince should i keep between lights and plant top?

the temps started to rise in the grow area

Thanks


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## 4u2sm0ke (Mar 4, 2008)

Temps will Raise..keep an eye on them...The distance for 400 is 12-18 inches I think...Be sure to check with back of your hand..I have a chart I will find after work...By then someone will have helped you..But I think 13 is a lucky #

Good luck my friend..


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## Fretless (Mar 4, 2008)

http://www.marijuanapassion.com/forum/showthread.php?t=1968

   Start around 12" or more, and see how close you can get them, it is largely dependent on ventilation.  The heat stress symptom is easy to see, a sort of weird wrinkling of upper leaves.


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## red_ss (Mar 4, 2008)

Thank you guys.. when i was using 1 400hps i keept it about 13-16 from the top and the temps was perfict about 72-77 .. now after the 2nd hps when i keept the lights about 20 inches from top the temps were about 78-82 so i moved it up to 23 inches and the temps on that hight seems to be the best about 73-78?? even though im opening the closet and i have afan to blow air! also the room have an A.C!! when i turn the AC on i cant sit in the room comfortably its very cold about 65 int the room? its eighter me cold or plants hot.. so  what do you think should i keep only one 400 hps at 15-17 inches! or 2 at 23 inches..

Thanks


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## S']['()|\|3D (Mar 4, 2008)

whats the square foot of the room??


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## red_ss (Mar 4, 2008)

S']['()|\|3D said:
			
		

> whats the square foot of the room??


 
sorry idont know ihate math dude.. the room is very big but the plants in the closet


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## POTUS (Mar 4, 2008)

red_ss said:
			
		

> sorry idont know ihate math dude.. the room is very big but the plants in the closet


 
If you have a tape measure or even a 12 inch ruler, you can figure out the size of the closet.

Measure how many inches long it is and how many inches wide it is.

Then just post the measurments. I'll show you how to turn that into square feet of area.


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## Puffin Afatty (Mar 4, 2008)

I use a 430w SonAgro, I can get my unshielded bulb up to 7-8 inches with no harm to tops.  the 400 is effective from 8-22 inches.


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## Puffin Afatty (Mar 4, 2008)

red_ss said:
			
		

> Thank you guys.. when i was using 1 400hps i keept it about 13-16 from the top and the temps was perfict about 72-77 .. now after the 2nd hps when i keept the lights about 20 inches from top the temps were about 78-82 so i moved it up to 23 inches and the temps on that hight seems to be the best about 73-78?? even though im opening the closet and i have afan to blow air! also the room have an A.C!! when i turn the AC on i cant sit in the room comfortably its very cold about 65 int the room? its eighter me cold or plants hot.. so what do you think should i keep only one 400 hps at 15-17 inches! or 2 at 23 inches..
> 
> Thanks


 
_spread the lights on the same plane, 40 inches apart, 12-15 inches from the plants_


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## smokybear (Mar 4, 2008)

12-15 inches seems to be the general consensus on distance from the plant tops. Just be sure to keep and eye one the tops to make sure that there is no signs of heat stress. You should be fine though. The more light the better so I would definitely go with both of the lights in there. Good luck and I hope to see some pics in the near future. Good luck and until then, grow it big my friend. Take care.


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## red_ss (Mar 5, 2008)

POTUS said:
			
		

> If you have a tape measure or even a 12 inch ruler, you can figure out the size of the closet.
> 
> Measure how many inches long it is and how many inches wide it is.
> 
> Then just post the measurments. I'll show you how to turn that into square feet of area.


 
Thanks bro.. the width is 40 inches / length 75 inches / side 21 inches


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## red_ss (Mar 5, 2008)

Thank you guys.. i know thats the distnce sould be bettwen 12-22 and it was perfict with me before with only 1 400 hps i used to keep it very close! and temp is perfict! but now with both lights next to each other side by side i must kep them about 23 inches from top of the plants and the temps almost 80? im keeping the closet door open


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## POTUS (Mar 5, 2008)

red_ss said:
			
		

> Thanks bro.. the width is 40 inches / length 75 inches / side 21 inches


 
If you were drawing it on the floor, one side is 40 inches, and the other is? There can only be two different measurements....I'm not sure what your third one is.


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## Puffin Afatty (Mar 5, 2008)

red_ss said:
			
		

> Thank you guys.. i know thats the distnce sould be bettwen 12-22 and it was perfict with me before with only 1 400 hps i used to keep it very close! and temp is perfict! but now with both lights next to each other side by side i must kep them about 23 inches from top of the plants and the temps almost 80? im keeping the closet door open


 
_*:hairpull: 23 inches is too far to be of any use to your plants.  spread the lights out at least 40 inches horizontally.  the effective radius of the 400w HPS is 20-22 inches, beyond 22 inches your plants wont get the intensity of light they need.  that said, no point in putting the lights together, you wont get any further penetration, still only 20-22 inches.

  Using 2 400 w is not the same as a 800w bulb, as the 800w has twice the penetration of the 400.  

the advantage with using 2 bulbs is that you can horizontally spread the lights, or if you were doing a very tall grow you could put one on bottom and one on top to get light to that part beyond 22 inches from bulb. *_


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## red_ss (Mar 6, 2008)

POTUS said:
			
		

> If you were drawing it on the floor, one side is 40 inches, and the other is? There can only be two different measurements....I'm not sure what your third one is.


 
the third is the side of the closet..forget about it just think of 1+2

Thank you


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## red_ss (Mar 6, 2008)

Puffin Afatty said:
			
		

> _*:hairpull: 23 inches is too far to be of any use to your plants. spread the lights out at least 40 inches horizontally. the effective radius of the 400w HPS is 20-22 inches, beyond 22 inches your plants wont get the intensity of light they need. that said, no point in putting the lights together, you wont get any further penetration, still only 20-22 inches.
> 
> Using 2 400 w is not the same as a 800w bulb, as the 800w has twice the penetration of the 400.
> 
> the advantage with using 2 bulbs is that you can horizontally spread the lights, or if you were doing a very tall grow you could put one on bottom and one on top to get light to that part beyond 22 inches from bulb. *_


 
So 2 400hps dont mean 800? i cant spread them because im keeping them as far as possople from each other.. about 3 inches, that all i can do because the size of the closet.
Thanks


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## POTUS (Mar 6, 2008)

red_ss said:
			
		

> the third is the side of the closet..forget about it just think of 1+2
> 
> Thank you


 
Ok, here's what you have:


40 in = 3.33333 ft or 3 ft and 4.0 inches

75 in = 6.25 ft or 6 ft and 3.0 inches

So, 3.33333 x 6.25 = 20.8333125

Rounded, it's 21 square feet of area.

At 3,000 lumens, 21 x 3,000 = 63,000 lumens are needed to grow at a minimum.

At 5,000 lumens per/sq ft, (5,000 x 21), you need 105,000 lumens.

Each of your 400's should be about 50,000 lumens. The two you have will work just fine for your grow area.

Space them evenly across your grow. The space from the wall to your light and from light to light should be the same.

How wide is the reflector on each of your lights?


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## Puffin Afatty (Mar 6, 2008)

red_ss said:
			
		

> So 2 400hps dont mean 800? i cant spread them because im keeping them as far as possople from each other.. about 3 inches, that all i can do because the size of the closet.
> Thanks


 
ok, then in this case I suggest you forget about the 2nd light until you get a bigger area.  that little closet is tooooo small for 2 400w bulbs.


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## red_ss (Mar 6, 2008)

POTUS said:
			
		

> Ok, here's what you have:
> 
> 
> 40 in = 3.33333 ft or 3 ft and 4.0 inches
> ...


 
Thank you buddy for that math calss lol.. i started to love math because of you 

the reflector is small! its only 10 inches squered reflector


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## POTUS (Mar 6, 2008)

red_ss said:
			
		

> Thank you buddy for that math class lol.. i started to love math because of you
> 
> the reflector is small! its only 10 inches square reflector


 
Hey, that's cool man. If you look at my crude drawing made in "Paint", you'll see the measurements your should follow to hang your lights.

This will space them evenly and give you the most from your space.


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## red_ss (Mar 7, 2008)

Ill take a good look at that.. Thanks again


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