I've been watching this thread, but haven't posted much yet. I have seen the issue as well. I posted this in my local forum:
My approaching year old 58 is 100% T5's. As many have seen, my new 180 is feed by dual 400w MH's.
I still say T5's are a great technology, but having used them for a year I think we still have a TON to learn. I love the cost, the low heat, the color combinations, etc. My corals have grown well under the lights. I bought a 3 headed hammer from Zeppelin maybe a half year ago, and it split to 6 three or so months back, and is the process of splitting to 12.
Downside, my colors of my corals have gradually gone away (there are a number of threads in the forums here,
THIS being one of the best ).
I'll give you an example...
I was lucky enough to recently see Porky's tank (has to be one of the craziest softie/LPS tanks I've ever seen, VERY sweet). I finagled another frogspawn torch combo off of him last night to compare/contrast as it grows under MH's instead of my T5's over the next year or so. When the new frag started opening, I realized how much T5's have changed the colors of the old one.
Going way back, here is the original picture I took back when I got the first frag:
Although a different camera, different settings, different photoshop work... all in all it looks almost identical to the frag I got yesterday even though the new one is stretched out loosing a little of the dark colors:
Now.... take a look at how the original frag is doing after 6 months under T5's:
You can imediatly see the color has lightened significantly. Is it in bad shape? I'd say no way. As a matter of fact, it just got done with it's first major split. It eats well, and I have no reason to think it has issues.
Looking back on my old pictures, there are a few frags that have this same symptom.
Long story short, although there are exceptions out there, and although corals may grow GREAT under T5's, the technology still has a long ways to go because we're obviously missing SOMETHING the corals need (or giving them something they don't want). Is it color spectrum, too much intensity, too little intensity, who knows...
Now, don't think I'm 100% MH yet at this point either. I bleached some SPS frags that were DOWN on the SAND, while my MH's were 14" above the tank (i.e. 16" above water). I still have some to learn there.
I'm thinking about getting a new lighting setup for my 58g 3' wide tank now
I've had some SPS and such under MH, and have not yet noticed any color difference. I moved one of my "bleached" (ok, so it's not bleached per say, just some color loss) hammers to the new tank under the MH to see how quickly and how much of its color will return.
Think/reply as you will. I'm no MH fan or T5 hater. Just take it as food for thought.
