Unless I missed part of a conversation, I can't help but wonder about lighting bandwidth changes over time. Will a low quality 420nm LED drift from that bandwidth earlier than a higher quality one. And, if so, does it shift enough to make a difference to the coral?
Good question, but I'll be surprised if you get an answer. When I ran T-5's I repeatedly asked this question concerning data about spectral shift over time. I was told to change my bulbs every 9 - 12 months because of it......but even though it was repeatedly asked, no one could supply that data. However, like a good little sheep, I changed my bulbs every 9 - 12 months. This is one of the reasons I switched to LED's and would now like to know the answer to the question you raised about LED's as well.