T5s and bleaching LPS - anyone noticed this?

[sphelps]

Originally Posted by Myka

Oh come on now Steve, there is no issue, it's a discussion - just an oddity that I was wondering if anyone else shared similar experiences, or had any ideas as to why this would happen. The T5s were the exact same bulbs (as stated above), removed from one fixture put into the new one. One Fiji Purple and one AquaScience 17,500K. However, I noticed bleaching with all the other T5s I had tried in the last 2 years as well (Giesemann and Hagen). I suppose they had different reflectors and different ballasts running them, so there may have been a bit of a change there, but I would think not much. They went from a Hagen fixture to a Degenbao fixture.

I was simply confused and was looking for clarity, I don't have a problem with the discussion which is why I'm participating. But it sounds like your problems are related to your previous lighting, if you always experienced problems with the T5 only setup, it's likely you didn't have sufficient lighting, especially if adding more intense lighting fixed the problem. Less than 80W is not very much light for any reef tank. It's not normal for T5s to bleach LPS corals, on average they will usually do better with T5 lighting over halides. Since my T5s stopped working in my fixture my LPS corals have not been looking too well, the halides still appear to produce enough light for the tank but it seems fairly obvious the T5s definitely add something the LPS corals like.

Also I'm still confused how your corals have been bleaching and have shown tissue loss for 2 years yet you still have them?? It also sounds like you've changed lighting many times which can also add to the problem you're observing.

I should also note that bleaching refers to the loss of color in a coral which is caused by death or loss of pigmentation of the zooxanthellae. Bleaching does not directly refer to tissue loss. Different lighting spectrums produce different results for coral coloration, sometimes giving the effect of bleaching. I've dealt with many people who experienced this, usually right after buying a new coral from a tank with different lighting. This is the only reason I mentioned it before.