Hi, I have a Kohler San Raphael one piece toilet that has always seemed to need the jiggle technique to get a good seal. I replaced the flapper once with the original Kohler part, but I wondered if maybe one of the pros would recommend a different brand or replacement for the Kohler part that would work better. The original Kohler number on the toilet is K 3397 and the number on the flapper I used is 42388. I have a well and it drives me crazy when I hear the pump kick on....I know the toilet is leaking! Thanks for any suggestions!