Will this work

[Bob I]

[quote="Don E"]

Some people would definitely assert that the actinics are necessary- I'm a bit sceptical. They certainly do look good. People claim they reproduce the sun's light filtered through ocean water at typical reef depths. I'm inclined to think the appeal is more aesthetic than practical (and may have something to do with the fact that many reefers will pay a LOT of money for lighting equipment, and retailers know that...) I'm still reading about it before I make up my mind.

I have long maintained that what you say is correct. Sunlight in the tropics at noon is 6500K. As you move deeper into the water some frequencies are filtered out, and the light appears more blue the deeper you get.

Therefore if one provides light of 6500K, one provides all the correct spectrum for growth., but blue is purty, but in no way necessary for coral growth.

However, for looks it is necessary, as a lot of corals fluoresce under actinic light. This is especially true for many zoanthids. If you really want to see the nice colors it is best to provide some actinic lighting. That is what I have found anyway.