315 cmh vs led

beercan

Well-Known Member
So i think im to the point that i need to change bulbs in my 315w cmh fixtures, pretty expensive bulbs to be changing every year or so, my last run yeilds were way lower than expected, i also run 260 w leds from hlg as supplemental lighting to the 2 315's in a 4x4, so should i go all led or change bulbs in 315s? I was looking at a timber fixture or perhaps buying a few more 260 w hlgs
 

Dape Green

Well-Known Member
I changed my 315’s at 1 yr or so, that’s when I felt I started losing density as well. So at 300$ in bulbs per 12-14months it made the higher priced LEDs nut seem so crazy. I’m on my first run right now with a HLG scorpion and am blown away. I mean there is zero shade in there.
 

Gemtree

Well-Known Member
I've had a igrowtek cheapy bulb off amazon going for 6mo now and seems good for half the price
 

Norml56

Well-Known Member
Are these Genetics you've run in the past with much better results? I've never experienced a change in bud quality or yield for the worse, and I'm also running CMH with HLG QB boards. I wouldn't ditch the CMH for all LED unless you are having temp problems. The 2 lights really compliment each other IMO
 

Norml56

Well-Known Member
You'll spend more on electricity heating an all LED space up to 80F+. Also, the CMH gives off UV that the LEDs don't, so you'll need to supplement that too. (Solarcure, etc).

Phillips bulbs engineered for longer usable service life with less degradation.
The UV output on CMH seems to be debated quite a bit. I've seen tests done by growershouse that shows UV output but others say that the glass used to make the CMH stops the UV. I know that Hortilux makes a special CMH bulb that they claim allows the UV.
 

Norml56

Well-Known Member
I should have worded that different lol, im running 2 315 cmh and 1 260 hlg led, i added led when bulbs were a year old in cmh fixture's they run non stop
I'm assuming by non-stop you mean that you Veg and flower in the same tent. Is that correct? You should caculate how many actual hours the bulb is on.
 

Norml56

Well-Known Member
Based on a rough guess of 2 months veg and 10 weeks flower that is 2280 hrs of bulb on. About 6,840 hours a year. I would personally run that bulb for 2 years before replacing. You are still well below the 20,000hrs at 85% PPF Maintenance. If you are replacing every year you for sure aren't seeing a drop in quality/yield because of a worn out bulb.
 
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