We have two Kohler Model K4471 pressurized toilets. Both are on the same floor level. One flushes great. The other take two flushes, sometimes more, to flush everything down. Is there an adjustment that needs to be made on the pressure tank? Or is it a different problem. We have only lived in this home (built in 1995) for two months and this problem existed when we moved in. Thanks for any suggestions. Ron