If it was a light issue, chances are you would also have increased algae and diatom growth.

I have noticed more posts than normal recently about SPS "problems" - My theory is they don't like loud Spurs playoff games in the same room as the tank :P

Seriously though, our weather is changing, temps higher, AC running, evaporation rates are higher, Tank temps fluctuate more ... is this a seasonal thing? A few of my SPS have some die off too, and I seem to remember a similar pattern this time last year?