BTW, you can always check the spectral plots of a bulb via sanjay's or the mfg to see how much blue spectrum irradiance is being emitted from your "daylight" bulb. It's probably half of that emitted from a dedicated actinic. But, if you're trying to determine what combo of bulbs will achieve the perfect balance I think the PAR meter can get you very close to your goal. Install only the daylight, take the PAR reading. Then, remove the daylight and install all the actinics it takes to match the daylight reading. Do they make "daylight" bulbs in dedicated nm's like the do actinics? You'll probably end up with a purple cast once the balance is achieved. You can add whatever bulb to make it more pleasing to the eye, just compensate for the excess blue or daylight irradiance levels indicated in the mfg spectral graphs.