is this light safe to use again?

[joedub]

Hi everyone, I'm currently in between grows, resetting and cleaning up my grow area, when I noticed what I initially though to be a crack in my light bulb, but now looks like some type of imperfection also it's kinda cloudy brown, wasn't like that when I first purchased it, I've only used it for about 2 1/2 months. It is a Eye Hortilux dual arc light, the imperfection is on the metal halide end, was wondering if anyone had any experience w/ these lights and would you grow w/ this same bulb? any help in keeping my grow area fire free is greatly appreciated.

 

[DrGreenThumb@OZ]

ummm you sure its not just from the heat as its an element that burns so that looks like normal residue ..

 

[mcqueen]

take it back and get another one. dont mess with anything electrical. I am paranoid about that stuff. I had same problem and eventually it blew. I am worried if I am not at home and something happens...

 

[joedub]

@drgreen
so your using the same light and that happens also? it kinda freaks me out because it's not a light residue it's pretty heavy, also it's only on the metal halide side and I've only done one grow w/ this light.

@mcqueen
that's exactly what I'm afraid of, I would hate to come home to a burned down house, but also wouldn't want to cause a racket if this is normal, no one else I know uses the same type of bulb, but I'm wondering for you MH users out there does it start to residue after a while? keep in mind that the residue is inside the bulb so it's not something I can wipe

 

[TGT]

It is normal to get a build up of residue at the base of the bulb, depending on a few variables, such as how old the bulb is, how many times has it been used and also the potition of the buld and degree of angle the bulb is on when in use. Also, it is very common to have imperfections in the glass when from the factory. I have had many bulbs like this and none have caused a problem.

On the other side of the coin, it could be a slight gas leaking from the quartz filliment inside theglass tube causeing this build up of residue. If it is from this reason most likely the bulbs gas will shortly be depleted and the bulb will just go out or fail to ignite. I don't think you or your home would be in any danger, but if I were you I would bring it back to where you bought it and exchange it with a new one. Especially since it is such an expensive bulb.

Hope this helps and let us know what you find out, good luck!


TGT

 

[superultramega]

ummm you sure its not just from the heat as its an element that burns so that looks like normal residue ..

No there is not an element that burns. http://en.wikipedia.org/wiki/Metal_halide#Operation

Unless you see a crack I wouldn't worry about it. That's just what MH bulbs look like after they've run for a while. They start to look like a used flash bulb. (that kinda dates me) Sort of a film on the inside of the arc tube usually with some little bits here and there.
But if you're worried, take it back to the store and have them put their eyes on it. I can't really see anything in the pics. Don't be surprised if they tell you it looks normal. What you're describing sounds normal though.

 

[Mickymouse]

Theres a ceramic covered rod that glows red hot in HPS bulbs.

 

[joedub]

thanks again for all the replies, I ended up taking it back to the shop to exchange it, the shop told me that it was normal for the build up and that the bump was not an imperfection but was part of the manufacture, they then got a brand new one out to put my mind at ease. on the brand new bulb it had the odd bump also, as well as a slight residue, guess it gets noticeably worse after first cycle. I'll use it for one more cycle, possibly two? how often do you guys change out bulbs? I bought a Sun Analyzer(http://www.popularmechanics.com/home_journal/gardening/1273676.html) light meter but not sure if it reads accurately enough for me to go off of, or it's for out door maybe? http://www.popularmechanics.com/home_journal/gardening/1273676.html

 

[superultramega]

2-4 cycles. That's about 1500-3000 hours (assuming 60 day flower, If you're using the same bulb to veg add those hours as well). The output in lumens of MH bulbs drop off rather quickly. At 3000 hours they run at around 80% of the initial lumens. So do the math. How much is a 20% reduction in production costing you compared to the cost of a bulb? Say a 1000watt produces 1 lb when new, at 3000 hours it's only producing .8 pounds. Pretend you sell it for $4k/lb, that 20% reduction in final product cost you $800. It's just a matter of optimizing your return on investment. You might think one run, but the lumen efficiency of the bulb does not deteriorate in a straight line, it drops off faster as the hours on the bulb increase.

Your HPS degrades at roughly the same rate.

I'm curious how well those combo bulbs work. I've never noticed much difference between MH and HPS bulbs in terms of production. I've flowered with both and saw no clear difference in production.