A few things that you could start to look at here.
One is lighting. I would start by comparing your lighting to the lighting that the anemones were under when you bought them. Is it similar? Do you have more light? Less light? This is anecdotal, but I've found that my bubble tips tend to do best under about 200 par.
Like always, water parameters are also something to consider. When I have fish, coral, or invert issues, one of my first moves is to give the tank a full testing rundown. At a minimum, this will help me rule out major water parameters as the issue.
Third is flow. While this isn't likely the cause of your anemones changing color, you want to make sure that you're not blasting them directly with flow and stressing them out. Anemones will *usually* move around when they're unhappy with their flow situation, but not always.
@revhtree , maybe we can move this to the Anemone & Clownfish Discussion to get more eyes on it?
