I've been following a thread on another site -- about the same topic and I run the Lumenarc III and actually talked to CoralVue about the topic....The Lumenarcs are very nice indeed, but they actually weren't designed for the aquarium hobby, but for plants......But like anything else they were adopted over, but the LumenBright fixtures were researched by CoralVue and they reflect light better than the Lumenarcs. I heard rumor, that both reflectors were tied to CoralVue from 1 of my suppliers and asked CoralVue about that as well, and he didn't give a comment, which I heard there was a "legal" issue so CoralVue dropped the Lumenarcs'........I was also told that what is out there as far as the Lumenarc stock is old stock and they are trying to deplete in inventory.....I have done some calling around and the Lumenarcs aren't readily in stock as of last Thursday, but you can do some hunting and have them brought in if that's what you decide on to use......