metal halide lighting

[myrph]

I have a 150 gallon (72lx18wx21h) tank with a few fish and starting to make a planted tank. I don't have enough wattage with the current 120 watts worth of strip lighting and would like to buy a couple hanging pendant metal halides.. I was thinking two 175 watt lights, but I'm confused on what I need for "k" rating. I've seen everything from 6500k to 100000k .. what do I need?
Thanks,
Chris
Power usage.. will it make my electric meter spin wildly out of control?

[PaulasPets]

I have a 10,000k light on my marine tank, but for a planted freshwater tank I would reconment a 6500k as the 10,000k light is a bit more blue, making the plants look a bit dull.
For the power consumption: MH lights are cheaper than other types of lighting. I'm not 100% sure about the power consumption, but the total running costs (power + lamp replacements) are lower.

Paula