OK... You can also use t5's to target blue 420nm also. They are sold as fish tank lights. Actinic 420 Bulbs, they also have Actinic 460 Lamps. But if you have the choice for your blue light it's best to stay below 445nm. Fluorescent and t5's are ok as supplemental blue light sources. But if you don't have 440nm blue LED's I would use a small MH mixed with the blue fluor's for the blue light source. Of course this is providing your trying to do a 24 hour flowering and not a standard 12/12.

So my question is what type of flowering are you trying to do?