PM sent re:T5 fixture Gene.
replied, very interested!
It's so much cheaper to run than halides, and it's almost the same price as T5's + bulbs. You gotta think LEDs last years.
it is all relative...
i will never keep SPS corals. so realistically two 150-175w metal halides would work on a 48" long tank with supplement actinic lighting or i can just run the same metal halides with 20k radium bulbs and i won't need supplements. Metal halide light fixtures are super cheap right now (~$100.00) and so are the bulbs (~$40.00). Now, factor in a decent dimmable (it has to be dimmable because at 100% they are way too bright) LED light fixture that would work for a 48" go for $600-800.00. And LEDs are still somewhat unproven technology when it comes to coral health (bleaching) and how long the LEDs really last.
yes, heat is an issue, but the power savings 120w (LED) vs. 300-350w (MH) is very little, i think i calculated it around ~$20.00 per month depending on my light cycle. which would mean that even with changing the MH bulbs every year, i would need to run the LEDs for at least 2-3 year to get my money back. Not worth it to me.
just my opinion and i'm not trying to turn this into an argument, especially since i'm contemplating going t5.