You will need to experiment, as your particular room and house levels will be unique. It can take a day or two to figure out what works best. The way I set mine up is to pick a good spot for my humidity gauge such as in the middle of the temperature range in the cage and out of direct line of the basking lamp, when the cage is fairly dry (not right after spraying). Check the reading. Run the humidifier until the gauge reads TOO high such as about 80%. Record how long it fogged. Shut off the humidifier and time how long it takes for the level to drop below what you want the cage to stay at such as 40%. This tells you how long your fogging cycles need to be and how long the humidifier can stay off before it is needed again. Remember, the key is to provide cycles of humid and drier rather than one constant high level. That's not necessary. There are plug in lamp timers and programmable timers that give you multiple settings possible every 24 hours. In fact, there's an add at the top of this forum from LLLReptile today for one. When you spray (the humidifier fog itself won't produce enough dripping water for the cham to drink, but helps keep him from dehydrating as much between sprays) the level will go up too, but that's OK.