DE MH lamps and UV

[Fishy888]

One of the tempered glass UV shields in my MH/T5 lamps shattered a couple of days ago. I’ve taken it out of service until I can get some tempered glass cut to size.

It got me wondering though about whether these lamps produce as much UV towards the end of their lifetime as when they’re new. I know the visible light spectrum shifts towards longer wavelengths as the lamp ages.

So do they still produce UV, especially UVC, in the same amounts they did at the beginning of their lifespan? My lamps will need to be replaced within the next 6 months or so. I can see a small amount of black soot in all three lamps.

I’m not running that particular lamp and thankfully I don’t have any corals under that particular lamp although a BTA recently moved to a spot under it. Would it be too risky still to run it? I assume so which is why I took it out of service. It’s a 250w plusrite lamp.

 

[A. grandis]

Don't run without the tempered glass. It should take up to 5 days for you to receive your glass from the moment you ordered, depending on where you live. Do the right thing. DE lamps without tempered glass protection will damage your corals no matter how old those lamps are. UV-A and UV-B will also be greatly intensified! You will do no damages to the corals if you leave them without light.

 

[Fishy888]

Don't run without the tempered glass. It should take up to 5 days for you to receive your glass from the moment you ordered, depending on where you live. Do the right thing. DE lamps without tempered glass protection will damage your corals no matter how old those lamps are. UV-A and UV-B will also be greatly intensified! You will do no damages to the corals if you leave them without light.

I figured as much. My thoughts were that the UV could potentially even be greater than when the lamp was when it was first installed.

I’m leaving the light off until I can get some glass back in. It’s bad enough that the light ran potentially for as much as 5 hours like that. My fish are fine thankfully and all but I don’t want to chance it. The corals won’t be without light though because each halide runs on its own ballast. I already unplugged the ballast that controls the light with no glass.