MH-DE nomenclature

T Man · 05/30/2007, 11:00 AM

I recently replaced my three MH-DE 150W/10K with 20K's. One of the bulbs has a pile of ash inside and what looks to be some type of sensor with the center gone. The bulbs have served me well, my question is what is that paddle shaped object with a wire fixed to the glass? A sensor or indicator of sorts or maybe even an ignitor? Here is a photo of two of the old bulbs side by side for comparison. Any feedback would be appreciated, Thanks. TinMan

PaulErik · 05/30/2007, 01:12 PM

That is a getter. It is used to absorb impurities such as hydrogen, vapors and hydrocarbons inside the outer bulb.

Cleaner the atmosphere is longer the arc tube/lamp will last. At high operating temperatures some impurities can diffuse into the quartz arc tube and alter the performance of the lamp.

From the picture it looks like the getter failed from to much heat or just got exhausted.

T Man · 05/30/2007, 01:52 PM

Thanks PaulErik, I understand how it works now. I would hope that the failure was due to exhaustion- I don't even want to think about heat issues. Anyhow it was time to replace the older bulbs, I have been thinking about the 20K's for some time now- I can honestly say that the colors in my tank seem to pop out even more under the bluer light. Thanks again. TinMan

05/30/2007, 11:00 AM	#1
T Man ~PPPPPPP~ Join Date: Jan 2006 Location: Emerald City Posts: 1,045	MH-DE nomenclature I recently replaced my three MH-DE 150W/10K with 20K's. One of the bulbs has a pile of ash inside and what looks to be some type of sensor with the center gone. The bulbs have served me well, my question is what is that paddle shaped object with a wire fixed to the glass? A sensor or indicator of sorts or maybe even an ignitor? Here is a photo of two of the old bulbs side by side for comparison. Any feedback would be appreciated, Thanks. TinMan __________________ He that can have patience can have what he will. ~ Benjamin Franklin Current Tank Info: click the "TzFuture" folder in my profile

05/30/2007, 01:52 PM	#3
T Man ~PPPPPPP~ Join Date: Jan 2006 Location: Emerald City Posts: 1,045	Thanks PaulErik, I understand how it works now. I would hope that the failure was due to exhaustion- I don't even want to think about heat issues. Anyhow it was time to replace the older bulbs, I have been thinking about the 20K's for some time now- I can honestly say that the colors in my tank seem to pop out even more under the bluer light. Thanks again. TinMan __________________ He that can have patience can have what he will. ~ Benjamin Franklin Current Tank Info: click the "TzFuture" folder in my profile

05/30/2007, 01:12 PM	#2
PaulErik Premium Member Join Date: Dec 2000 Location: North Charleston, SC Posts: 1,703	That is a getter. It is used to absorb impurities such as hydrogen, vapors and hydrocarbons inside the outer bulb. Cleaner the atmosphere is longer the arc tube/lamp will last. At high operating temperatures some impurities can diffuse into the quartz arc tube and alter the performance of the lamp. From the picture it looks like the getter failed from to much heat or just got exhausted.