PRODUCING DRIER DRY ICE FOG
First, cooler water gives you a drier fog. It also gives you less fog, but if you get enough for the effect, this can help cut the amount of moisture on the stage.
Second, don't discharge the fog directly on to the stage floor. Run it through a length of hose that goes down, then up, and then down to the floor level. (Think of an upside-down under-sink drain trap.) The heavier droplets will be trapped in the hose in the first dip. Water will collect there, so plan to drain it regularly or you will wind up with a blocked hose.
Third, some people put a sponge at the bottom of the hose outlet. This will soak up any water that might run out of the hose from condensation inside the hose. Plan to wring out the sponge regularly; if you let it get saturated, it won't do the job for you.