well, for comparisons of the light bulbs, check out Sanjay Joshi's light bulb tests on the lighting forum. he has made extensive scientific tests on a wide variety of lamps, ballasts and reflector systems the past many years. Very good Info.,
you seem to be asking a variety of questions in one. for pure PAR value, it is my understanding that nothing beats a true full spectrum daylight, 6000-6500 Kelvin metal halide lamp but while it provides great broad spectrum light energy to grow corals, it does not make them look their best due to the yellow appearance. but it does actually have a huge amount of blue and actinic spectrum. it's just washed out by all the red, green and yellow in the light which also promote growth. so the higher kelvin lamps produce less par but a higher percentage of blue light. which makes coral colors more vivid.
I have seen excellent reef tanks , like a 180 with 3 250w 6500K MH lamps for growth and 2 x 160W VHO actinic for color enhancment. coral growth was phenominal. and color appearance very good too. corals grew to huge sizes. like tree leathers with trunks 8 inches in diameter. and acro's branching all over the place. and clams doing very well too.
so the question is, Charley the Tuna, do you want good looks/ or good taste? the best top reef corals grow in 5-15 feet of water which is about 6500K from the sun. but they wont show their pigment color that well under straight 6500K in the wild. some actinic supplelement brings it out in our tanks.
recently i've seen some club members 22 inch deep tanks running 6 x T5's. and they looked very nice too, indeed. a mix of bulbs, 2 x actinics, 2 x 50/50, a 10K and a daylight. great looking corals and colors.
tank depth should determine the lamps and wattage you choose. depending on what you want to grow.
I don't know if i'm right or wrong. but this is how i understand lighting for reef tanks. the combinations of lamps, wattage, ballasts and reflectors is almost endless.
