420nm or 450nm actinic?

[harlequinnut]

Hi, I would like to know if I should go with the 420nm or 450nm actinic blue power compacts? My lighting system consist of 2X175w mh(10K) and one actinic blue pc.

 

[lion_crazz]

Go with the 420. It penetrates deeper.

 

[harlequinnut]

Thanks, I also found this website that had a sunpaq dual actinic 420/460nm bulb for sale. Would that be a good choice also rather than going with the 420nm?