Overloaded AM1000

The water temps here in Brisbane, Australia are early 30's now. My AM1000 can't keep up with the CO2 injection rate. I was thinking of putting a simple T on the CO2 line (into a seperate needle valve), and pushing only as much CO2 into the AM1000 as it can handle (in dual venturi mode), and then feeding any additional CO2 into a cheap powerheads impellor to mist throughout the tank.

Does this sound like a reasonable idea?

I could buy a second AM1000 and pump, but eventually the hot weather will be over and the single AM1000 should be ok again.

Scott.