Thanks BigDave , got all Vaseline off and ended up having to shave a tiny bit at the whole to make it bevel(?) a bit to get it to slip down. It was the recommended unicel C-5315 through this Amazon site and it is working perfect now, still real snug. Everything seems to be working and water is clear. CarlD, Have FC at 5 this morning. Got double extra drops for my Taylor kit so I can be more exact. I'm guessing I'm not too good of a guesser with the OTO so don't want to risk the guessing game again. :O)