I didn't stay at Holiday Inn last night but I am a chemist. Let me add a couple of comments to the thread:
-A fully dehydrated dessicant pack will continue to absorb water from the air until it is in equilibrium with the surroundings. Uptake is slow and the time it will take to get to equilibrium depends a lot on relative humidity. Once equilibrium is reached, the desiccant won't absorb any more moisture from the air. A pack won't continue to work very long in Biloxi, Mississippi, in August.
-The desiccant packs can be reused many, many times if you bake them in a 225 degree oven for a couple of hours. After dehydrating the packs, store them in an air-tight container. Don't mix fresh packs with used ones. You can also use a microwave oven to recharge your packs, but I would suggest using a low setting to avoid overheating the paper/plastic envelopes.
[Microwave ovens do what they do because the frequency of the microwaves used corresponds to a rotational frequency of water molecules. The microwave radiation causes the water molecules to absorb kinetic energy, which in turn causes the object to heat up.]
-If you are using desiccant packs with an indicator (turns blue or pink depending on the indicator) when recharging, don't rely on the color of the indicator as the indicator used (mostly Cobalt Chloride) will change color faster than the desiccant dehydrates, hence my recommendation that you bake them for a couple of hours at least.
-As mentioned above, loading your housing in an air-conditioned space will help. Air conditioners lower relative humidity. An additional tip that I picked up from a video engineer that I dive with, is to use a hair dryer to warm the inside of the housing and the camera before closing. By warming the air, you reduce the relative humidity in the air space even more.
-It is important that you recharge, before using, any desiccant packs that you get from shoe stores, electronics, etc. as they are most likely fully hydrated and useless by the time you get them.
-When finished diving, only open the housing in an air conditioned space if possible and quickly place the desiccant packs in a dry air-tight container.
-Four 2-gram dessicant packs fit neatly inside the PT-015 housing. By following the above protocol, I can reuse the same four packs for several days of diving before the indicator fades a little, at which point I replace them with four new ones.
