I am thinking you will still have enough PAR for your tank residents, but I am also thinking that with even only one 10000K tube you will lose the wondrous colors you are experiencing with only the actinics. I am having similar problems on a smaller scale. I have two 28W pc bulbs on my 15G zoo holding tank. Just the actinic gives wonderful glowing colors. The problem is that it is only that particular actinic gives those colors. My other actinic bulbs on other tanks are not as great.
You might find that you will have to have a period in the day where you can enjoy the great colors, and the rest of the day not. Maybe schedule a sitting in front of the tank with a glass of wine time.
