Adjust the Fill ValveRemove the lid from the Kohler toilet tank. Squeeze and slide the C-clip on the float rod of the fill valve, in order to adjust the tank’s water level up or down. Slide the C-clip up in order to raise the water level. Lower the water level by sliding the C-clip down. Test flush the toilet several times, in order to determine if the water level is filling to the proper height, as determined by the Waterline mark within the tank. Adjust the C-clip as needed.Adjust the FlapperRelocate the flapper chain S-hook to the bottom hole in the lift rod, and reposition the S-hook on the flapper chain, to provide more flapper chain if the flapper ball does not seat properly when the lift rod is lowered.