An actinic bulb would shine with a deep blue color. It is certainly not what you want. If you are really interested in this being a live plant tank, then I would start by reading this sticky, which articulates the details you will need far better than I am capable:However, the old 20 gallon still has all its hood parts, including the light. It is a fluorescent actinic bulb, I am pretty sure, and is still in working order. Will this bulb be appropriate for my tank?