# MH / HPS life expectancy



## October420 (Aug 6, 2016)

Hey everyone,

I just finished my 5th grow, CBD's Crew Sharkshock. This is my first grow using HID lighting, my previous four grows were done with a MARS 192 x 3 W LED. So I actually learned to grow (began to learn) using LED's. My Mar's started to fail during my 4th grow but I still manged to get the grow in by rotating my two plants during bloom. 

So for my Sharkshock grow I decided to give HID lighting a try. My grow tent is only 32" x 32" by 84" tall so I picked up a Yield Lab 400 W light kit with a 400 W digital ballast and a couple 400 W MH and HPS bulbs. I have 536 hours on the MH bulb and 540 hours on the HPS bulb. My question is how often do most of you change bulbs? Because of my limited space I'm mindful of the need to produce good quality buds so if there is a lot of diminished returns in using my bulbs for two grows I'd prefer just biting the bullet and buying a new set of bulbs. I did purchase a Digilux 400 watt HPS a few weeks ago so it's ready to go if needed. 

For a point of comparison between my experience using LED and HID I averaged about 2.5 oz per plant of bud using my LED. Using the 400 watt MH and HPS bulbs I yielded 4.61 oz of bud and about 2.5 oz of Popcorn buds and Sugar trim. However not sure if this is a fair comparison because in the past I always grew two plants and this last grow I only grew the one plant.

Peace


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## Rosebud (Aug 6, 2016)

Hi October, nice to see you. Sounds you got a nice harvest off those plants. Thanks for telling us your harvest weight. good to know.


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## Rosebud (Aug 6, 2016)

I changed bulbs every year.


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## October420 (Aug 6, 2016)

Thanks for the info Rosebud. I believe both bulbs are rated for 12,000 hours. Seams like a stretch to me. But if I ran them as you said you run them changing them yearly that would be around 2200 hours per bulb per year, that sounds much more realistic. 

I forgot to mention for this last grow, not only did I switch from LED's to HID I tried the Gas Lantern Schedule. I may stick to it if I keep getting the yields this last grow produced. It also helped keep the temperatures down slightly in my grow tent. 

Peace


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## Surfer Joe (Aug 7, 2016)

With bulbs costing only about $20, I usually get a new one for each grow. I keep the others as backups.
I have checked with a light meter and found that there is some reduction of intensity from the same bulb over time, so older bulbs are probably not emitting the same amount of light as when they were new.


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## zem (Aug 7, 2016)

I go a year on them as well, never had one burn before I had changed it. I only do it because I know the lumen output must be significantly less by then, but one would not notice it visually


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