I prefer the look of 10,000k and actinic bulbs. I think 6,500-6,700k lights look really yellow compared to my tanks still using the saltwater bulbs the fixtures came with. Actinics do add some useful light and adding lots of blue light tends to make plants grow shorter and wider while lots of red light makes plants taller and thinner. It's just not as much useful light as if you added 6,500-10,000k spectrum because you have an excess of blue and not enough red or other light. I did have some wonderful growth adding purple plant gro bulbs with the actinic and 10,000k.