Lamp Type ....................Watts.... Lumens/bulb ....Total efficiency
Fluorescent Bulb ..............40................3000........... 30k lumens
Mercury Vapor................ 175.............. 8000 ............20k lumens
Metal Halide................... 400 ..............36000 ...........36k lumens
High P. Sodium ................400.............. 45000........... 45k lumens



Notice the Mercury Vapor lamps are less efficient than the fluorescent (FL), and can not be positioned as close to the plants, so the plants will not be able to use as much of the MV light. The light distribution is not as good either. MV lamps simply are not suitable for indoor gardening.

Good luck and have a good grow!:thumbsup: