You may find that none of this helps, and the problem in fact, is the same as the one I had. Theres a red gasket in the head itself, which Eheim wont sell you. Some shops have this part. When you prime, sometimes if the gasket is a little sticky, the primer twists this "red canister sealing ring" as its called apparently, and it leaks. It took ages to come up with the right answer, and a major wet floor. nevermind, got it sorted in the end. :clap:
