You only have 20 watts. Not sure how the conversion from incandescent goes, but you're running at 2 watts/gallon in terms of light requirements for inverts and stuff.
If I understood right you have 2 seperate bulbs? When it's time to change your bulbs next you might look at switching to 1 straight 10K bulb and 1 straight 03 actinic bulb. The 50/50 bulbs are ok, but they are more general purpose. What I mean is that you have one bulb trying to do 2 jobs, but not doing either job as good as it could. You get a "more true" light spectrum from using dedicated bulbs. At least that is my understanding of it. It will also give you the option of having only the actinic or only the 10K on, assuming that the fixture has seperate plugs for each bulb. Sorry, I'm not real familiar with fixtures that size.