Over 20 years ago Philips market the Actinic 03 bulb for use in the medical industry to help treat babies with jaundice (from what I can remember). The Germans in the late 80's didn't have the Kelvin rated metal halide bulbs we have today. The most common for reef aquariums at the time were the 5500K and 6500K bulbs. Of course, everything was superbright and some started supplementing the Actinic 03 bulbs to help improve the color of the corals and for the viewer. Long story short, these bulbs have been marketed by almost every aquarium lighting manufacturer since it adds a depth no other flourescent bulb can achieve. Even though the lux rating on the bulb is relative low compared to alot of the new bulbs out there, it still works. I've supplemented Actinic 03 bulbs on my tanks since it was first used and continue to this day.
I hope I have my history right...:scratchch
I hope I have my history right...:scratchch
