315 CMH distances - Page 2 - Growroom Lighting - International Cannagraphic Magazine Forums

digging · 11-20-2017, 02:53 AM

What distance should a 630 de CMH be from the canopy ?

Spaventa · 11-21-2017, 01:12 PM

The distances people are reporting for a 315 are crazy! anything from 6" to 48"!

Im not calling anyone a liar - Im amazed at how wide the range of usable distances is! I know myself, as others have said, that even at greater distances of more than 2 ft you don't get any stretch. I also noted better development of lower bud sites, despite my expectation.

Ive not pushed the other end of the range. I haven't ever run the light closer than 18".
I find 2 ft gives me all the penetration and power I want with the spread I need to cover the area perfectly. I don't have a plant directly below it and never had any hot spot issues at all.

jaded1 · 11-21-2017, 01:24 PM

For me the perfect height is 15in from top of plants,any nearer and the footprint they cover is too small.

Spaventa · 11-21-2017, 02:08 PM

I also believe that going closer than 18" exceeds the rate at which the plant can photosynthesise so its wasted light over a certain level of intensity.
CO2 rooms could logically run closer but only by as much as the metabolic rates rise in the plant, maybe 20% at 1000ppm? I don't know but in a vented room at atmospheric co2 levels I doubt many genetics will make use of being closer than 18". These are just my observations.

jaded1 · 11-21-2017, 03:40 PM

I feel it's a bit strain dependant,have been running a lot of sats lately and they seem to be able to take that intensity with no issues

Spaventa · 11-21-2017, 04:12 PM

Quote:

Originally Posted by jaded1

I feel it's a bit strain dependant,have been running a lot of sats lately and they seem to be able to take that intensity with no issues

Yes this is one example of what I was talking about when I mentioned genetics. Some use more light than others. I think we only differ in our conclusions on this by a few inches and genetics account for that

moose eater · 11-21-2017, 07:46 PM

I have several of the 315cmh's. I tend to maintain 14" - 20", and assert that Natural High's statements are fairly solid with my experiences thus far..

zachrockbadenof · 11-25-2017, 10:25 PM

i got my 315 today and set it up- since my ladies have been veggin under 8bulb 4ft fluor, i have it about 2+ feet about them- givin them a bit of time to adjust... i did the hand test... man they run cool... i can put my hand 2-3inches from the bulb with no heat problem... my temps this morn in the tent were 64/65f... with the 315 on... maybe 2degrees warmer... so far pretty impressed...

mean mr.mustard · 01-20-2018, 02:46 PM

I'm willing to participate.

Let's see what happens.

senor coconut · 01-20-2018, 06:22 PM

Thanks for starting this thread because after the first experience with this lamps I'm a bit confused too...
I run a single 315 on a D-Papillon type reflector, only for flowering... for vegging I use PLLs.
I found that the hand test is not so significative with these kind of lamp, I used to start flowering with a distance of 12 inches from the canopy then progressively arriving at 8.
I did not get a real burn of the tips, no curling signs but I've noted that the leafs on top were more pale/yellowish than the ones in the lower branches... next cycle I'll try to start flowering from 18 or even more.

11-21-2017, 01:24 PM	#13
jaded1 Member Join Date: May 2009 Location: u.k Posts: 934	For me the perfect height is 15in from top of plants,any nearer and the footprint they cover is too small. __________________ [SIGPIC][/SIGPIC]
	Quote

11-21-2017, 03:40 PM	#15
jaded1 Member Join Date: May 2009 Location: u.k Posts: 934	I feel it's a bit strain dependant,have been running a lot of sats lately and they seem to be able to take that intensity with no issues __________________ [SIGPIC][/SIGPIC]
	Quote

11-21-2017, 07:46 PM	#17
moose eater Senior Member Join Date: Aug 2017 Location: Off a dead-end dirt road, near a river, out of town, in the hills and trees Posts: 1,178	I have several of the 315cmh's. I tend to maintain 14" - 20", and assert that Natural High's statements are fairly solid with my experiences thus far..
	Quote 1 members found this post helpful.

11-25-2017, 10:25 PM	#18
zachrockbadenof Senior Member Join Date: Nov 2007 Posts: 1,684	i got my 315 today and set it up- since my ladies have been veggin under 8bulb 4ft fluor, i have it about 2+ feet about them- givin them a bit of time to adjust... i did the hand test... man they run cool... i can put my hand 2-3inches from the bulb with no heat problem... my temps this morn in the tent were 64/65f... with the 315 on... maybe 2degrees warmer... so far pretty impressed...
	Quote 1 members found this post helpful.

01-20-2018, 02:46 PM	#19
mean mr.mustard I Pass Satellites Join Date: Feb 2005 Location: Overturning Pebbles and Upending All the Animals Alight Posts: 6,418	I'm willing to participate. Let's see what happens. __________________ Life's most persistent and urgent question is, "What are you doing for others?" - Martin Luther King Jr. People seldom do what they believe in. They do what is convenient, then repent. - Bob Dylan Be good and you will be lonely. - Mark Twain How wonderful it is that nobody need wait a single moment before starting to improve the world. - Anne Frank
	Quote

11-20-2017, 02:53 AM	#11
digging Member Join Date: Apr 2010 Posts: 153	What distance should a 630 de CMH be from the canopy ?
	Quote

11-21-2017, 01:12 PM	#12
Spaventa ... Join Date: Oct 2006 Posts: 1,505	The distances people are reporting for a 315 are crazy! anything from 6" to 48"! Im not calling anyone a liar - Im amazed at how wide the range of usable distances is! I know myself, as others have said, that even at greater distances of more than 2 ft you don't get any stretch. I also noted better development of lower bud sites, despite my expectation. Ive not pushed the other end of the range. I haven't ever run the light closer than 18". I find 2 ft gives me all the penetration and power I want with the spread I need to cover the area perfectly. I don't have a plant directly below it and never had any hot spot issues at all.
	Quote

11-21-2017, 02:08 PM	#14
Spaventa ... Join Date: Oct 2006 Posts: 1,505	I also believe that going closer than 18" exceeds the rate at which the plant can photosynthesise so its wasted light over a certain level of intensity. CO2 rooms could logically run closer but only by as much as the metabolic rates rise in the plant, maybe 20% at 1000ppm? I don't know but in a vented room at atmospheric co2 levels I doubt many genetics will make use of being closer than 18". These are just my observations.
	Quote

01-20-2018, 06:22 PM	#20
senor coconut Newbie Join Date: Dec 2012 Posts: 30	Thanks for starting this thread because after the first experience with this lamps I'm a bit confused too... I run a single 315 on a D-Papillon type reflector, only for flowering... for vegging I use PLLs. I found that the hand test is not so significative with these kind of lamp, I used to start flowering with a distance of 12 inches from the canopy then progressively arriving at 8. I did not get a real burn of the tips, no curling signs but I've noted that the leafs on top were more pale/yellowish than the ones in the lower branches... next cycle I'll try to start flowering from 18 or even more.
	Quote