Grow Lights

I just purchased a table top greenhouse for a Ficus, it has a grow light with 3 modes, yellow, yellow with pinkish purple, and pinkish purple. I'm wondering which is the best mode to use. I live in the northeast and during the winter direct sunlight is scarce and maintaining a good humidity level is difficult so I thought this greenhouse would help with both. Any help would be greatly appreciated.

Thank You,
Joe Reid

That is impossible to answer given the information suplied. The one and only way to evaluate a light is to get PAR values and compare to the plant needs. Quality grow lights comes with PAR information. For other lights you need to get a PAR meter yourself or find readings online.