Plant response to less light: positive! Our electricity was out for just a few minutes the other day, and when that happens in the middle of my light cycle, it won't turn on until the next "event" is triggered in the timer. In this case, the main lights had just come on for the day and nothing else would happen until it switched to blue 'moonlight.' I didn't feel like tinkering with the override settings, so I just left it lights-out for most of the day. Thought: well, maybe that will knock out some algae, and it won't be long enough to kill anything.