I had a mild panic on the weekend, after two full days of diving. I'm using a Nauticam EM-5 housing and flat port. I always rinse the housing after every dive. I opened the housing to change batteries and download images twice, and each time inspected, lubed, and refitted the port and body o-rings. After the final dive I put the camera in a cooler full of fresh water for a long soak. Only my camera and strobes were in there, nothing else, and they were not dropped abruptly. I'm the only one who uses the cooler so I know it was not disturbed.
When I returned after 30 minutes, the leak alarm was beeping! I quickly dried the exterior and extracted the camera. There were only a few drops of water inside the housing thankfully, and in fact I could not quite see how there was enough to even trigger the alarm. Nonetheless, there was water inside which cannot be a good thing. I inspected the o-rings again very carefully and could find no evidence of anything that would have caused a leak. The o-rings are about a year old and have done maybe 100 dives. What I cannot quite understand is how the housing did not develop a problem during 5 dives at depth, but then leaked a little during a gentle soak.
Any advice? I would like to know if there is any way to determine the problem myself through inspection or in a pool first. Sending the housing for service will be a major pain as it would have to go to Singapore, so I would miss out on probably a couple of months of use at the best time of the year here in the Philippines, but if that is what I have to do then I will.