I cleaned the Oring, checked to be sure the trays and media were in place. Still leaked. Tried replacing the Oring.. Still leaked.. Then I checked the clamps to make sure all is nice and tight. It doesn't seem to "lock" down tight but does seem to creat a decent seal. It is not a total failure. The leaks are down the side of the canister along each side of the indentation where the clamps are. It started as a slow drip.. and then got much worse the more I played with it. We first noticed it when the filter was shut off then turned back on.. odd.. Wish I could tell you more.. The reviews I have read fail to find the "exact" problem as well..
Marc