Thanks Coolermeister for the pics. This is the same issue I ran into. The BP felt like it was tight, but the o-ring wasn't sealing. Once I replaced them with a larger o-ring all was good. This is one reason I wish companies would not use a recessed hole for fittings. I had a similar issue with the new Swiftech Micro-res due to the recessed hole on the bottom. I do not see the benefit of recessed holes and I am not sure why companies have been doing it lately. It would seem to me that a flat surfaced tapped for fittings would be easier to do and better for sealing.