Yes, teflon without them also leaked. Bashsea got back with my LFS and advised that I just use E6000 on the threads and secure the fittings permanently to the lid (that is how Bashsea secures the 90 degree NPT to barbed fittings that are most common on their lids - but when we asked for a solution that allowed for a vertical fitting, the o-ring solution is what it came with). I'm going to try E6000 next.