400w MH bulb choice

Hi, I'm deciding on which 400w mh bulb to get for vegetation and am not certain the difference between the various temperature grades that they are sold in. I'm guessing that I'm looking for something in the 6500k range for ultimate blue output but I've seen others past 10000k. What's the difference? Thanks!

Ps. Would welcome any recommendations on specific brand.

MJ

The 6,500 K (Kelvin) tubes most closely resemble natural daylight. The 10k are a different color tint.

I use a Hortilux Blue MH bulb for my seedlings. Would recommend.