Two of my three tanks have actinic blue 03 bulbs in them. I am not a science/physics guy, so I will explain what I have learned about these bulbs in my own layman's terms. From what I understand, o3 blue is ideal for coral, in fact some companies market there 03 blue bulbs under names that suggest they will be used in a saltwater tank set up. In all my reading about actinic blue 03 lighting I haven't read anything that suggests that there are bad affects on the fish from this source of light. I have noticed that my plants love this type of light, and that I have increased green algae growth in my tanks (which is just fine since I have snails. The algae growth isn't out of control or anything, but I have had to cut down on the amount of time that the tank lights are on so that I don't get a cloudiness to the water (when using an actinic blue bulb, water that is green and cloudy just appears cloudy, you can't really see the green of the water) All the fish that I keep are for the most part night predators, so that is why I started using just actinic blue lighting, but now I would put actinic blue lighting on ANY tank for ANY type of fish, it is that appealing!! I would recommend to some of you to mix and match, like using 50/50 bulbs that are half actinic and half daylight (many bulb manufacturers make these kinds of bulbs) this way you would have both spectrums but still have a blue tinge that is very appealing. If you have a two bulb set up I would go with 1 actinic and 1 daylight bulb. a three bulb set up I would go with 2 actinic and 1 daylight bulb. As far as bulb manufacturers go I have had great results with coralite bulbs and would totally recommend them. There are bad actinic bulbs out there, I had one that lost all it's blue spectrum in about 2 months, this was a bulb given to me as a gift, and the brand wasn't printed on the bulb, I can't remember the name of the brand. I have told many people that once you start playing around with actinic blue lighting you can't be without it! Have fun!