Hey guys, thanks for all the replies.
I upgraded to these Tek Lights under the promise of better growth because the bulbs have better PAR. Switching back to the Coralife T5s wouldn't make it better because those are fairly weak lights to begin with.
I'm beginning to think it's a chemistry issue because I have a Gorgonian frag that's been growing steadily with superb polyp extension (the frag is 3 inches long now and the polyps are nearly an inch when extended). Some corals do "good", some flat out die on me.
The other coral that seems to do well is GSP, which has quadrupled its surface area in my tank (started as a frag too).
I've taken a look at some of the chemistry articles provided here on Canreef (like balancing Ca and Alk) and I think that's what I should dwell into to improve coral health, but everything seems so steep and technical.
Where do I start? Should I change the way my setup is run?