03 Actinic lights have a special Phosphor in them which allows them to emit true blue light right at 420 nano meters (the blue spectrum). "Blue" lights are basically normal white bulbs with a blue filter, these lights filter out everything but the blue spectrum and allows it to pass through. These lights dont emit much light bc most of it is filtered out.
From what I know this is true, we will see if anyone can further help clarify.
I had blue bulbs and i got 03 actinic - I would 100% suggest the switch! Promise you will love the change.