It's a guarantee, that a little bit of moisture is going to get into your rirst stage, dispite your best efforts. I would'nt worry unless you get an unusually large ammount into it. It sounds to me like your taking care to clean it as well as possible, although there is an increased risk that by blowing air around the filter opening you could force water in. I just let it sit for a fiew min. and before packing up, or changing tanks, just blow on the connection before cracking it. And turn the yolk down so that no water leaks in, wipe it off, and cap it. Normal annual svc. has never turned up any problems of any kind. But I do agree that if you drop it into salt water you better get it to the shop.