Sorry about the double post guys.

Anyway....

I went into my local hydro store and asked about the issue you brought up Khyber. That being me running a 1,000w bulb converted by an interchangable ballast at 600w. I told the guys exactly what I had, and how I was running it. He told me the exact opposite of what you said. He told me that running the 1000w bulb at 600w was not only conserving energy, but prolonging the life of the bulb itself.

2 very different opinions.... someone please clarify.