View Full Version : MH bulbs
04/10/2006, 09:39 AM
Ok so I'm about to sound like a complete newbie here BUT...
What is the life expectancy of an XM 20K bulb (400W)? Does anyone know of a place to find out this kind of information?
I had some bulbs previously (maybe radiums???) that were actually only expected to last like 6 months, but I thought the XMs lasted longer for some reason. I gotta replace my current bulbs and I can't remember which kind I have (pretty sure it's XMs, but I know they are 20K).
Really though, I am just wondering about typical life expectancy of the different kinds of bulbs.
04/10/2006, 10:19 AM
I'd like to tag along on that one. I replace all my non MH bulbs (PC's and VHO's) at 6 months, my SE MH bulbs at 9 months, and my DE's at 12 months. I know they should have more life than that, but you can tell a huge difference from all bulb changes even on that schedule. That also builds up your spare/reserve bulb stash.
04/10/2006, 10:50 AM
I read that Metal Halides were typically good for a year at 10 hours a day. You will lose intensity over the course of that year just like with any bulb (down to ~85% for 4000 hours of on/off burn time), but that isn't the main issue. The main issue is color spectrum, which I read that MH will typically hold for a year before needing to be replaced. I am fairly new at this myself, but I understand how light works in general.
If I had to guess, I would say that actinics or 20000K lamps could safely go longer than 10000K lamps because if the color fades it has longer to pass through the acceptable ranges before it hits the algae-growth ranges.
04/10/2006, 12:51 PM
It actually also depends a lot on the type of MH bulb you get I think. I thought that certain types...like XM vs. radium vs. ushio...would last longer than others. That's really what I am wondering about but the idea of 20K lasting longer than 10K does seem to make sense to me.
Gary I typically go about a year before replacement but I think ideally I should replace them sooner.
04/10/2006, 04:44 PM
I had about the same schedule in mind as Gary did. I think, by the time anyone finished a real life test of say 10/hrs a day for X months, hanging over salt water ~ half of the bulb manufaturers would have changed, or will soon change, their manufacturing methods, or materials providers, or something... like moving production to CHINA.
04/10/2006, 10:29 PM
I was told by a light wholesaler that one should have a light meter to record your new bulb intensity and check them and when they start to drop off significantly in intensity its time to change the m. halide bulb. This sounds like it makes since but thought I'd add this to the confusion?
04/11/2006, 06:34 AM
Are light meters expensive ? I could see how one would be a good thing to have. That way you know if you "need" to shell out over $100 for new bulbs or not.
04/11/2006, 07:06 AM
A cheap one is ~$20. But it only measures intensity and not color spectrum (which degrades the bulb to an unusable level faster than intensity will).
04/11/2006, 10:01 AM
Aquatic Specialists used to have one. I remember checking my bulbs with it a long time ago.
04/12/2006, 05:02 PM
The radiums burn out the quickest. 6 months from what i've always read. PM Logan (logman17) over in our forum mel. He is an ushio rep. He could tell ya more i believe.
04/12/2006, 06:18 PM
04/14/2006, 11:04 AM
I think alot depends on the ballast used for life of bulbs. I am looking at the new 14k 175watt Iwasaki bulbs. Andy (CEO for Icecap) told me I could get up to 2 years of use with this bulb and his ballasts. I already owned the ballasts when I asked him about the bulbs so no need for him to sell me.
04/15/2006, 09:34 AM
Does anybody in the club have a quantum meter? I think that would be a great resource.
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