I agree with the above. It is probably a good idea to get the amp checked out. It should not be blowing mosfet fuses repeatedly like that. Is the amp adequately ventilated ? Is your CA-200 a rear or side heatsink version ? I have a CA-300 (biased to factory recommended setting by yours truly) and it never gets hot driving my PSB Stratus Gold i's, which drop to around 2.7 ohms in the midbass.
A CA-300 would give you a little more headroom at about 50% of the cost of a second CA-200. Similarly, you could sell the CA-200 and get a CA-400 for roughly the same as a pair of CA-200s.
A CA-300 would give you a little more headroom at about 50% of the cost of a second CA-200. Similarly, you could sell the CA-200 and get a CA-400 for roughly the same as a pair of CA-200s.