Humidity seems to make a great difference too. If you have low air flow and high humidity, the haze will just hang and hang, and you can use the low setting on both the fan and the haze and it will look great with even coverage. We did an outdoor show last night and started in such windy conditions that we thought the hazer (a cheap Chauvet 2D) would be useless. The first set was in daylight so the hazer was off. By the second set, the wind died down and it got very humid, and we had haze aplenty for a 30 x 16 stage and a crowd of about 500 ppl.