I've read the entire thread, but if the answer to my question is in there then I was probably too dense to recognize it. Nevertheless, this seems to be the appropriate thread to ask the question.
Using a luxmeter, is there a way to determine whether an HPS bulb is failing? For example, if a I have a 1000W Eye Hortilux Super HPS bulb, is there a standard unit of measurement I could read with my luxmeter to tell whether the bulb is working properly?
Reason I ask is I have just such a bulb, and a few days ago it suddenly seemed to give off significantly less heat than it had been. I can't really tell with my naked eye whether the light has dimmed - it's still very bright, but doesn't seem as bright as a 1000W should be. I know that could be my mind playing tricks on me, so I want to measure the bulb's intensity, but I'm afraid I don't know how.
Using a luxmeter, I get a reading of consistently between 65500 and 67000 lux measured 1 foot directly below the bulb. But I have no idea how to use this information to tell me anything about whether my bulb is working properly, because I don't know what the reading was a foot below the bulb before I got suspicious of it.
Is there a way to do that? Some sort of charts or conversion tables somewhere that will allow me to take that value and compare it to the known values of a "healthy" 1000W Eye Hortilux bulb? Is there a standard distance at which I should be taking the reading? Do I need a PAR meter, or some different unit of measurement than lux? I know this probably sounds like a stupid question, but this has never come up for me before. But it would be useful information in the future, too, so that I can more objectively track the status of HPS bulbs as they age, and perhaps help me better anticipate when they need to be replaced. I tried looking up the information on Hortilux's website, and all they say is that none of that matters. Trouble is, it kind of matters to me.
Thank you for any help you can provide.
bongwater
