Just make sure you are not clipping the input of it. If so, you need to turn the volume control from your mixer down a bit.
On my Soundcraft Ghost, I have a volume control for the Control Room level that goes to the amp. I keep my Hafler P-3000 turned up all the way (which is way too much power for the Events), but keep the Control Room volume down. This allows the amp to work properly.
I have always said, although this topic has not come up for some time on here, that you can have an amp rated at 150% off the power your speakers can handle. Speakers are conservativly rated, and amps tend to be liberally rated. Meaning, speakers can handle more power then they say, and amps don't deliver what they say they will. So, you can "overpower" a speaker by 50% IF don't clip the input of the amp. Clipping the input of the amp CAN cause the amp to output up to 5 times it's rated power. On a 100 watts amp, clipping the input would COULD create up to 500 watts at the output.
Turning down the input of the amp only makes matters worse. It not only decreases the input sensitivity, which is not disired, but makes it MORE sensitive to clipping. Weird eh?
So, turn the amp up, but back off the Control Room volume from your mixer. This will keep the amp running hot, which is what you want because the speakers will respond well to it, but will also assure that you don't clip it's input.
Ed