Hello All, This concerns a pressure case made from 7075 Aluminum and anodized to the following spec: 'MIL-A-8625 Type III, Class 1 including duplex seal on all components, 0.001" buildup/0.02" thick'. This case is several years old, and has pressure cycled in the ocean to several thousand meters a few hundred times. On the contact surfaces exposed to saltwater, that is, the mating surfaces on the high pressure side of the o-ring, it has started to show extensive bubbling. The bubbles range from one to several millimeters, and they chip off fairly easily, some can be simply rubbed off with a fingertip to expose the bare aluminum. The exposed aluminum does not look (to the naked eye) to be heavily corroded. Is this sort of failure something I should expect to see given the operating envelope for the pressure case? Can someone help me with a cause of what might be happening here? From other reading I have learned that impurities in the aluminum may be the culprit, but those seem to have shown problems earlier than I am seeing here. Could the pressure cycling be a factor? Thanks in advance for any help with these questions.