Lighting Little Sun Cool Hood 650w/Distance from tops?

[BustaB]

Hey guys Bustab here just a quick question about cool hoods, I recently switched to a Little Sun Cool Hood 650w Which emits almost no heat off the face of the lighting glass. I had it on a prior crop & experienced a bit of outer leaf edge curling as well as a bit of leaf spotting ( bleaching ) fixture was appx. 12" above tops. I can NOT adjust with the back of the hand method because it doesn't hardly put off any heat, can someone PLEASE tell me if there is a tried & true way of determining light height above plant tops with a cooled hood which doesn't emit hardly any heat ? Thanks much ahead of time, Bustab

 

[namvet25]

I'm not a hps user but 12 inches is too close with 650 watts.It's probably not the heat effecting your leaves but the light rays emitted from the light being to close.Iwould move the light up a bit and see if it helps.This is just my thoughts but we need someone with hps experience to join in so just sit tight.

 

[BustaB]

Thanks namvet25 I tend to agree about the light saturation as the cause of the curling & bleach spots on the last crop, I have been running Hydroponics since the late 60s & Aeroponics in the past 5 years or so always with my MH for veg growth & HPS for flowering stage ( Old guy Old ways ) However I have also always used a simple " Wing " hood & not a Cool Hood & most times once in Veg I go to my 1000w system but I am trying to save a bit on Electric & still get a good yield. I have had an idea but it may be kinda foolish, what would you think of pulling the glass from the hood without the hood cooling fan on & set it as I would with an open wing setup " back of the hand method " Then install the glass turn on the cooling fan & letter go ? Just a thought & thanks again for your response .

 

[A4]

Your problem is radiant heat and honestly you should still be able to feel the heat on the back of your hand but not as easily as you would without the glass as you are getting convection and radiant without the glass as opposed to just radiant with the glass. Of course with radiant heat, darker objects conduct more radiant heat than lighter objects and just like with setting in the sun and a cool breeze blowing, you aren't going to feel too hot until you go in for the day and realize your skin has absorbed all of that radiation and is burned to a crisp.

Short answer, there is no real good way to set lighting without a lux or lumen meter. I run 1000W HPS and set mine early on around 36" and as the plant gets accustomed to the light I drop it, ending up around 20" from the tops. That is still borderline as I get some curl but not too much.

Best of luck Busta!

 

[BustaB]

:drool:Thanks much for your post, what you say makes clear sense. Last night I went ahead & set things the old way by pulling the glass shutting down the cooling/exhaust fan, once cooled I fired it back up let it run for appx. a half hour & set it by the back of my hand, reinstalled the glass & turned the fan back on. I ended up with the face of the glass at 18 1/2" above the plant tops, as of tonight no curling & plants are reaching for the sky. This Little Sun Hood really stays cool, you can lightly touch the glass even without any burning & heat isn't really felt until about 2" away from the glass which is why I had a bit of a time setting it.

Thanks again
Let your path be cluttered with Big Beautiful sugary crusted buds!:drool: