I have two A360X on my 75 Gal. They have been running pretty good for almost 4 years, I have them set up toward the blueish side of the spectrum. But for the last 2 months or so, I have noticed that one of the lights will flicker and be come more purple. But this would eventually go back to matching blue color. But tonight I noticed one side has turned purpleish and won't go back to blue. Any suggestions on why this is happening? I have not adjusted the spectrum or time schedule for over 2 years