Monti caps aren't nearly as fussy about light sources because the zooxanthellae algae that inhabit a capricornis are growing pretty much horizontal, and just want tons of light. In my experience monti-caps actually thrive under point source, deep blue LEDs while the same light source would cause dead under-growth and lanky extension on SPS. Most of the anemic monti-caps I've seen with faded color seem to be under T5's.
Lots of debate about color temperature and it's affect on SPS, but a lack of hard data in the industry. By and large though most hardcore SPS growers I know swear that 10k halides or mixing in 10k T5 bulbs produce thicker growth than 20k lights.
The prevailing theory is while green/yellow/orange light has little PAR value for corals it does help the coral with growth patterns. Basically, a 10k light source tells a hard coral it's growing closer to the surface of the water while a 20k light source tells a coral it's deeper. So, under the warmer light source the coral would push more of it's energy into growing horizontal, and hence more spherical than vertical. I see a lot of SPS tanks under 20k or LED lights dialed in with too much royal that have 'lanky' or spindly growth.
Might be BS, but it also might explain why the old timers still like 10k lights.
