3700k Coated Metal Halide Bulb - OK For Flowering?

I'm going to use a 6500k MH 175w bulb for a closet grow and kick it with some CFL's on the sides. I am having major troubles finding a bulb to flower with. I found a few 4000k bulbs for my 175w ballast, but that doesn't seam like the right color for maximum bud production.

I did find this bulb. It's 3700k but it's coated. Will it work?

Bulb> http://www.bulbs.com/eSpec.aspx?ID=8470&Ref=Metal+Halide&RefId=112&Ref2=High+Intensity+Discharge+%28HID%29

I've also been trying to find a HPS conversion bulb, but not much luck with 175w. Lots of 250w and 400w conversion bulbs though.

EDIT:
Just found this conversion bulb, but gawd damn thats expensive!!!
HPS conversion bulb > http://www.1000bulbs.com/product/1798/LU0150-62345E.html

they are slightly better than nothing, buy more cfls if that's all you can afford.

I found a different HPS conversion bulb for $50. Been doing a lot of reading about these conversion bulbs. Looks like this is the way to go if you only have a MH ballast.