Well my brother, the culprit will always be the pump pushers. Should be at least washable, but you need to take the pushers apart an grease the inside rings and I always like to goob them up with silicone. Once sealed the pusher stays grease and none of it makes it to the case. Sealing the crystal with GS cement helps a lot. Also, check your crown tube sealing and use blue thread locker to make sure it's done right. Leaks are all about gasket areas being dry and no sealant where it needs to go. All of my pump pusher chronos have been good to at least wash weekly with a brush and warm soapy water with no leaks. Washing cars and playing in the pool. These are not divers though. The system was improved with the screw-down pushers, and still only good to 100m
Hope that helps.
E