Color temp shift with bulb age?

[junkwerks]

Has anyone noted (anecdotally or otherwise) a shift in color spectrum as a HID bulb ages? I only ask because of something I noticed recently in my own setup. My flowering plants had been yellowing for the last month or so, and not because of a nute deficiency/lockout or temp issue (I controlled for these with no results). It was something else.

I've been running a SunSystem 7 Dual spectrum for about 18 months with spectacular results. Great yields, few problems. The bulbs are due to be replaced soon. They're actually a bit overdue, but have yet to stutter or crap out at start so I've been keeping them in service. Poor housekeeping, I know... Fresh bulbs are in the pipe, but meanwhile I figured what the hell and tossed an old T-5 CF veg rig into my flower chamber to see if I could bolster the troops. JESUS! Not only did all of my plants respond by greening right back up, the ones that were under the brighter MH bent toward the CF tubes.

I know that people have tracked lamp intensity degradation over time, but has anyone noted color temperature degradation as well? This might be an interesting factor to take a look at and possibly a factor in choosing a lighting setup. I'm trying to dig up a buddy's color temp meter so I can put my hypothesis to the test. I have a feeling that my lamps, especially my MH has shifted away from the useful color spectrum and into the 3000k range, similar to a halogen lamp (ugh). When I have the new bulbs installed, I'll take another reading and see if there is any variance.

Research continues....

-jw-

 

[Hydro-Soil]

Has anyone noted (anecdotally or otherwise) a shift in color spectrum as a HID bulb ages? I only ask because of something I noticed recently in my own setup. My flowering plants had been yellowing for the last month or so, and not because of a nute deficiency/lockout or temp issue (I controlled for these with no results). It was something else.

I've been running a SunSystem 7 Dual spectrum for about 18 months with spectacular results. Great yields, few problems. The bulbs are due to be replaced soon. They're actually a bit overdue, but have yet to stutter or crap out at start so I've been keeping them in service. Poor housekeeping, I know... Fresh bulbs are in the pipe, but meanwhile I figured what the hell and tossed an old T-5 CF veg rig into my flower chamber to see if I could bolster the troops. JESUS! Not only did all of my plants respond by greening right back up, the ones that were under the brighter MH bent toward the CF tubes.

I know that people have tracked lamp intensity degradation over time, but has anyone noted color temperature degradation as well? This might be an interesting factor to take a look at and possibly a factor in choosing a lighting setup. I'm trying to dig up a buddy's color temp meter so I can put my hypothesis to the test. I have a feeling that my lamps, especially my MH has shifted away from the useful color spectrum and into the 3000k range, similar to a halogen lamp (ugh). When I have the new bulbs installed, I'll take another reading and see if there is any variance.

Research continues....

-jw-

Sounds about right.

Yet another reason to switch lamps every 3-4 (3-month) grows.

 

[Haps]

Your lights are about 20-30% of what the were to start with, and the MH gets bad fastest.

 

[GMT]

I actually replaced a 400w son-t yesterday, and had to redo the whitebalance on my camera because the pics were coming out a little orange. The bulb was at least 3 years old, maybe up to 4 or 5, I dont keep track of those things. I only replaced it because i replaced a broken ballst. I assumed it was an upgrade/change in the bulb spec, but now you mention it, it could have been due to the age of the old bulb.

 

[Mr. Pink]

So the brighter white light from a MH bulb means it is still good?

 

[swampdank]

I definitely notice a bluer spectrum from fresh Hortilux HPS vs Older ones.

I am loving the new bulbs. They just "feel" better.