pdxman1,

There is a worderfully simple test to determine this. Hold you palm over the top leaves. If the back of you hand is not getting too hot, you are OK. This is also assuming that your plant weren't just moved from a very low-light situation to the MH lamp. If so, place the light higher for a few days until the plants start to look like they are really digging the light. Then do the hand test.

Zink