MH ?

[medi]

Does anyone know of a surefire method to check if the spectrum has shifted on MH bulbs?

[Big_Pun]

im not sure but i think the bulbs have a life span rated in hours usually, so maybe someone can chime in who knows, most rsuggest about a yr

[medi]

That is pretty much what I thought. I was just hoping there might be a more accurate way to check the lifespan.

[justahobby]

there is a write up (search bstreep's threads) that suggests lighting decreases by about 25 percent within the first year. if you lower your lights to compensate you can potentially keep them 1-2 yrs. aside from that, test w/ a par meter and keep a log

[medi]

hmm...hadn't thought about tracking with a PAR meter. Now if I can just find someone who wants to donate one. :)

[txav8r]

$349 for this one

Apogee Instruments' Model QMSW-SS

[hobogato]

the thing is, the par doesnt decrease too fast after that first few months, but the color spectrum of the bulb shifts to a lower kelvin. this is because it takes more energy to make blue light. as the bulb becomes less efficient, it makes less blue and more in the direction of yellow and red.

[jlh81]

i do mine every year but at first i let it got 1.5 years and everything was fine

[alton]

I have had DE Coral Vue lamps lose 50% of there brightness in 8 months and have had Reef Flux lamps last 18 months with only a 10% loss in brightness. I use a foot candle/lumen meter. I do know if you keep your lamps above a glass cover they last longer than if they are open to the water. These type of meters are much cheaper. If possible buy one that has a remote water proof head that you can drop in your tank to check levels at a certain depth and or location.

[corruption]

Lumen is visible spectrum only, and not a very accurate measure of your lights age/intensity/fade -- PAR actually gives readings based on usable light spectrum, not just what the eye can see.. I wouldn't trust a Lumen/Foot Candle meter to accurately estimate bulb age.

-Corruption

[alton]

It has helped me keep my corals both SPS and LPS alive and thriving for 8 years. If you have 4000 ft candles at the lamp and 40 ft candles at the bottom of your tank when new. And then a year later 3500 ft candles at the lamp and 35 ft candles at the bottom, to me this is a good way to measure lamp fade/loss. Oh and by the way your lamps could loose 50% tomorrow and it would not be noticable to the human eye. Having some kind of meter is better than no meter at all.