Light Output of the Phoenix 14,000K DE MH Bulb Over Time
 

Here's some info for this old thread. I came across this article as I was Googling for Phoenix bulbs. It claims that the MH bulb that is being tested lost around 20% of its output by month 6. By month 12, it has lost 25%. By month 18, it has lost 30% of its output. By month 24, it has lost 34%. By month 27, it has lost 37%.


http://reefkeeping.com/issues/2007-04/ac/index.php

"The light output of the six Phoenix bulbs shows an initial decline over the first three to four months and then levels off at about 75% of their initial output. From these data I raise the question: “If a bulb is not replaced at six months, when it has lost 20% of its output, then why would we replace it at 12 months when its output has fallen only another 6%?” It may be more cost effective to plan the lamp number and placement based on 70-75% of the bulbs' initial output levels. "

"this bulb would appear to still maintain 70% of its output at 18 months, 66% at 24 months and 63% at 27 months of use. "

Neal If you ahvea ots of really nice corals then I would switch them out and ensure that you are having the lighting period shorten or have some type of cover like screen to put over the tank with the stronger bulb will bleach some of the tissue in the corals like SPS. I know if you are going to a higher Kelvin bulb then you need to dull the light some how like using screen like I have already stated. If you are going from a lower kelvin bulbs liek 10,000k to a 14,000 or even a 20K then its not as important...

HTH

but I think that others have posted the same answer or better ones then mine....:wink:

I hate this article sooooo much. It's a nice bit of work but people are completely ignoring why the author managed to get the numbers he did and IMO are going to big in for a big surprise when they try and duplicate the results.

He's using Ice Cap ballasts, this makes for a substantial difference in the bulb's useful life. You may be able to get close to this kind of life with other electronic ballasts but you sure aren't going to get anywhere near it with an HQI. 6 to 9 months with a Pheonix or Aquaconnect on an HQI and it's hosed.

They really need to make this point in the article.

What are you basing this off of?

Steve

So.......I'm running a Giessmann 250W DE fixture with an Icecap ballast and 13K Giessmann bulb and would like it a BIT bluer. I am coming up on the one year mark for the bulbs and am wondering if going to the Giessmann 14.5K is gonna be any noticeable difference or should I go to thier 20K or a different brand completely. I am just kinda scared that the 20K might be TOO blue. There are also 4 actinic T5s in the fixture.

Personal observation, you wouldn't have to look very far to find people that would agree with me though. I would love to do a test with the same bulb and different ballasts but I don't have the gear. Based on the published data for single test output on HQI vs electronic you can see that HQI ballasts drive the bulbs harder so it makes sense.