Shark Whisperer:
Excellent!!! Thank you all for the replies. Now that I think about it, the last two trips didn't have fresh water tanks for us to put our cameras in...totally makes sense. I will also put the desecant stuff in my housing too, just in case. Everyone was very helpful...Thank You!
Silica gel desiccant packs will solve this problem. They can be bought in most camera shops. Have one pack for every time you plan to open the housing on a dive trip? For me, this is usually once per day.
A couple of suggestions:
1. You don't want the silica gel desiccant pack moving around inside the housing. Find a place out of the way of all controls and away from any seal. Sticky-tape (sellotape) it in place, top and bottom, making sure you don't cover too much of the porous paper.
2. Silica gel desiccant packs take a while to absorb moisture. Put it in and seal the housing at least one hour before diving.
3. Silica gel desiccant packs can be dried out again in a warm oven but they are less effective. Fresh packs are better. Once you open the housing, especially if in a humid environment, the pack will absorb moisture from the air, limiting its ability to absorb further moisture and, if really saturated, may even release moisture. If the housing is to be open for more than a few minutes, replace the pack with a new one, just before closing the seal.
4. If possible, only open the housing in an air-conditioned place. Usually, in these days of mod-cons, you can find somewhere on the dive boat or resort where the housing can be opened in a cool DRY environment.
5. If possible, let the housing reach the ocean temperature before the dive. The camera rinse bucket is usually the best option. But, if you have done 1 thru 4 above, you wont need to worry too much about point 5.
Regards
Peter