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Lately I have been looking around at the different wavelengths available for atinic lighting. I currently am running Aquaticlife PCs with 2 10,000k and 2 atinics. I am wondering what wavelength others are using, and if they have used both whether they had better growth rates with the 420nm or 460nm?

When i was running PC's I ran the 420's and seen pretty good growth out of the coral's that you will see with PC's. I am running T5's now and I run a six bulb setup with something similar to a combo of the 460's and the 420's I also have two 10K's and the growth is a lot better.

I don't believe actinics help with growth. Justin you had more light than he does, I am guessing this is a 4x65 watt fixture with a uni reflecture, you had 2x 96 watt, 2x 65 watt, and a odno t12 actinic. You would get better growth from 2 actinic/10k and 2 10k, but may look kinda funny. I run a 6 bulb t5ho setup, 2x 660 icecap ballasts 3x ati blue plus, 2x ati aquablue special, 1x ati actinic, and 3x 9 bulb blue led. I think this is almost too much light at about 4 in above the water. I think you would get more light out of a 4 bulb t5ho fixture or retro, cheap or name brand than you would out of a 4x 65 watt pc light. I know you would have much better light penetration from the t5ho. pc's will loose about 75% of thier light in about 16 in, t5ho about 50% in 18 in, and halides 50% in about 24 in from what I have read on some of the testing on par meters.

I will admit I didn't do the proper research before I re-setup my tank, if I had I would have definately gone with T5 lighting. The setup did come with individual reflectors for each bulb though. As for what you said about the blue spectrum not contributing to coral growth might be miss leading. If you look at some of the articles about lighting on Liveaquaria and pacific east aquacultures you will find that they state that the blue spectrum very important to the health of corals. In the book The Reef Aquarium: science, art, and technology (written by J. Charles Delbeek & Julian Sprung) has an entire chapter devoted to lighting, explaining that most corals are yellow to brown in color because they most easily absrob the blue light. They also state that a lot of the warmer colors will not penetrate past 15-20 ft. of water, leaving only the blue spectrum to reach the majority of corals.