I have an Eheim 2217 on my 75g cichlid tank that sprung a leak recently. The leak is on the output side where the male and female connectors are. It only leaks when the filter is on and the male side of the connector's valve is opened. It started after I took it out of the cabinet the other day to clean it. At first, when I was looking at the male end, I thought it was missing an o-ring, since it seemed like there was a good spot for a second one. However, the other male ends on my Eheims do not have a second o-ring there. I even replaced the male side with one from another Eheim I have laying around and it leaked as well. I can't see any visible damage to any part of the filter or its hoses. I would appreciate any help you could provide.