If you drop the gain so you only see 500-600w at the ohm load of your sub you should be okay.
Or, you could buy a second AQ sub and run one on each channel without worry.
Im in a similar situation, I own a USA2300 (300wx2, or 900wx1) and my subs can only handle 300w each, so I will be using two (Kappa Perfect 10's).