interesting observation

[jfl14609]

today I replaced both of my metal halide bulbs and then tested par values of each what I found was interesting. both were reeflux 12k bulbs, but both had very different par values. they were almost 100 off. I actually never realized how much of a difference the type of ballast you have makes. the ballast with the higher value was a pfo hqi 250 w and the other was a normal ARO. Does anyone else run different types of ballast? have you noticed this as well?

[Gary Majchrzak]

The type of ballast that you use will always affect the MH lamp that you burn on it. HQI ballasts cause MH lamps (at the same wattage) to put out more PAR. It may also cause the lamp to burn at a different kelvin (usually "whiter" looking). HQI ballasts will also shorten the lamps useful life compared to as if it were powered by a "normal" output ballast. HQI ballasts are also (usually) slightly more expensive than their "normal output" counterparts.

Even different brands of "normal output" and electronic ballasts will cause the same bulb to burn differently....

[jfl14609]

I figured there would be some difference but I was really surprised at just how much and just as you said its much whiter than the other