Lil Stinkpot
Lucky Greenhorn
For a long time I have been confused about how colder air can hold less moisture. I would have thought that the reverse was true, with cold air being denser. Regardless of HOW it happens, here is why I feel it should be important to the terrarium keeper:
Humidity is a measurement of how much water is in the air, versus how much it is capable of holding. As the temperature goes down, air can hold less water and the humidity rises because the CAPACITY is going down with the temperature. It's like having a glass that is 80% full, and then you shrink the glass. The water spills over, leaving a glass that is 100% full, and a mess on the floor. That's how it is when the air cools. The "spilled water" is the dew all over everything in the morning. As the temperature rises, the glass is getting bigger again, and while a little water is returned (the dew evaporating), much is lost as air currents (and terrarium fans) carry it away, and needs to be replenished.
With a highland terrarium, where the temperature drops every night, this can cause problems the next morning. A good solution is a misting system, which replaces the lost moisture, sometimes faster than it is lost. An other solution for smaller terrariums is frequent misting, but this can get to be quite a drag over time! Yet another is a sort-of swamp cooler/mini wet wall set up, where air is drawn in through a sheet of water-saturated material. Some people have gotten really fancy, and hooked up a humidistat to their fogging system, and it would hold a preset range automatically.
Just my two cents.
Humidity is a measurement of how much water is in the air, versus how much it is capable of holding. As the temperature goes down, air can hold less water and the humidity rises because the CAPACITY is going down with the temperature. It's like having a glass that is 80% full, and then you shrink the glass. The water spills over, leaving a glass that is 100% full, and a mess on the floor. That's how it is when the air cools. The "spilled water" is the dew all over everything in the morning. As the temperature rises, the glass is getting bigger again, and while a little water is returned (the dew evaporating), much is lost as air currents (and terrarium fans) carry it away, and needs to be replenished.
With a highland terrarium, where the temperature drops every night, this can cause problems the next morning. A good solution is a misting system, which replaces the lost moisture, sometimes faster than it is lost. An other solution for smaller terrariums is frequent misting, but this can get to be quite a drag over time! Yet another is a sort-of swamp cooler/mini wet wall set up, where air is drawn in through a sheet of water-saturated material. Some people have gotten really fancy, and hooked up a humidistat to their fogging system, and it would hold a preset range automatically.
Just my two cents.