11/28/15 Performed water tests at 1 a.m. specifically because I spotted some STN in my tank all of a sudden.
Temperature late at night read 78.1 °F
Looking at the temperatures recorded by the Apex recently, I had a significant swing due to our weather change over the past 48 hours or so. The low was 77.1°F and the highest was 80.6°F, which is roughly a 3.5°F swing and more than I usually would allow. Maybe this is why three corals are reacting. Not sure, but it's definitely a consideration.