OK got the 12 head fogger now, set on humidistat at 80%. Swamp cooler is on thermostat set at 75F. I wired my old misting system solenoid to a thermostat and used a relay switch to activate the fan so I have a back up misting fan set at 90F if the other systems are not adequate during a heat wave. The interior environment is much better I saw 82F and 80%RH at mid day on a warm summer day!

Question, is it ok to run the fogger-humidifier 24hr/ day?

12 head fogger is in 120cfm fan is strong enough to blow the fog up 6ft or so which is important as the fog is heavy and settles to floor quickly. With Swamp cooler bringing in fresh and cool air, I decided to close and inactivate most of the auto cooling vents. I am seeing 80F and 60-80% RH so now GH is really an orchid house!

Question, can fogger run 24-7 if on humidistat set to 80%?

All I can tell you is that I did that, and the plants loved it.