There are a few factors that must be addressed, and all factors work together to make the environment optimal.
1) Eliminate humidity loss, a simple glass sheet over the enclosure will accomplish this.
2) Control air exchange, an aquarium air pump will force air into the enclosure at a rate that is noted on the pump itself. At least one full air exchange per hour is fine.
3) Provide a method of removing excessive humidity, a computer fan that exhausts air out of the enclosure at a rate of one full air exchange per minute is fine. This is where a humidistat comes in, the humidistat should be set to reduce humidity until it matches the level you desire.
4) Use a humidity adding system of some sort that is run on a timed cycle or a second humidistat, misters, foggers, etc. will all do the trick. The aquarium air pump can work double duty here if the output is placed under water, the bubbles will increase evaporation and humidity.
5) Ensure all electrical items within the enclosure such as lights are protected from excessive humidity and do not cause an electrocution hazard.
note: yes, a timer or two humidistats are required on the humidity adding part of this system, when a humidistat or timer is only used to add humidity there can be situations where the humidity level becomes excessive, when one is used only to remove excessive humidity there can be situations where the owner fails to introduce the proper levels of humidity in a timely manner creating excessively dry situations.
Timers can be used in conjunction with humidity adding devices to create a very realistic environment where rain falls when it should, fog develops in the morning, and the entire system stays within your set humidity levels.
I prefer to set timers up so that they power my humidistats, which in turn power the humidity adding devices. This causes a somewhat random schedule of humidity addition, our system uses misters which can go on any time between 6pm-7pm, 3pm-4pm, and 6am-7am if and only if the level of humidity is lower than desired.
Adjusting exchange rate also adjusts how fast the humidity levels fall, very fast exchange rates lower humidity faster, slow exchange rates slow humidity loss. Determining what works in your situation and for your critters is a matter of trial and error, I prefer not to have more than three misting events per day along with no more than a 5% loss in humidity between misting.
Using the above system gives you a ton of freedom from worry about humidity levels, I prefer it for its high degree of accuracy and elimination of human fault in keeping their enclosures environment as close to optimal as is possible.
Maurice Pudlo
. Extremely frustrating.
