The Lid provided was not flat across the lower mating surface with the top land of the fermentation tank and refused to seal. Removing the oring, the lid rocked back and forth, and any over-tightening to seal with the oring in place would have simply cracked the lid since the oring seals on the inner surface below the top land. Robin in Customer Service replaced the top lid along with a new oring on 11/5, which was an improvement, but I also added the spare oring above the replacement which finally sealed the top lid. To see the difference, flip the lid upside down and the lid sits flat, right side up and the lid rocks and the oring winds up high at one point and leaks. The new thickness oring may solve the problem, but for me, it took a new lid and two orings to seal the top. Nice first fermentation with storage keg purged with CO2 from the Fermzilla. Start pressure was 5 psi going to 18 psi with Blow Tie regulator on supply keg. No leaks. After clearing up, the same line goes over to the liquid post on the Fermzilla, and should transfer smoothly through the 3/8 line. Nice and easy.