Phoenix 14K PAR

[Rickyrooz1]

Found this interesting since I use Phoenix bulbs.

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. Initially, we could shield or raise the lights and then gradually lower or unshield them over the first four months or so, when the intensity is at its highest but falls most quickly. Beyond six months the bulbs' light output remains fairly constant at about 75%, so only minor adjustments would be needed for at least a year. Doing this may considerably extend the bulbs' effective life.

I have been in the habit of replacing my bulbs about once a year as is so often recommended. The measurements suggest that this may not be necessary, though. In my aquarium setup, my lighting is suspended by a pulley system, which allows the lights to be easily raised and lowered (see Figure 3 below). Lowering the lamps a few inches can easily compensate for a 25 to 30% drop in lamp output to maintain a consistent light intensity for the corals by decreasing the distance from the bulbs. Having a reliable light meter, I can measure the output of all seven of my bulbs in fewer than five minutes. I now target a PAR level of 400-500 for the most light-demanding corals, and adjust the light pendants’ height accordingly.

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

[ekovalsky]

I use these bulbs also and may hold off replacing them at 6-9 months after reading this article. Honestly I wasn't thrilled with their color at first (almost monochromatic blue on EVC electronic ballasts) but after a few weeks of burn-in they have transformed to white with some extra blue, and now they look fantastic without any supplementation. Considering their spectrum and efficiency with the electronic ballast the PAR is extremely impressive. I'm glad I didn't opt for 400w bulbs.

I may start taking photos of the tank monthly with identical manual exposure and white balance settings, to see how the spectrum shifts with increasing hours. Changes will be easier to detect this way, as I know even large spectral shifts can go visually unnoticed when occuringly slowly over a long period of time.

I'm running thre lamps staggered, with each on for 10 hours per day -- this will decrease if and when I rebuild the light rack and add the 4 x 80w T5 already here.

[Rickyrooz1]

Same here. The Phoenix looks like a 20K bulb when I installed them and after a few months look more like 15K bulbs. I love the blue spectrum these bulbs produce. They can be run without supplemental lighting.