Turn the knob clockwise to raise the water level to get a good flush or counterclockwise to lower the water level during times of drought.
To check condition of flapper valve for small slow leaks:
Check water meter dial is spinning.
Flappers comes in two sizes. It’s either 2″ or 3″.
Use the 2″ flapper for Glacier Bay Toilets 1.6 GPF (After 1994). Use Fluidmaster 5052GB Solid Frame for best seal. Don’t use the generic one size fits all, select the model specific for Glacier Bay.
Don’t use Korky brand. It doesn’t seal completely and has weak flush. Avoid more costly flappers featuring water conservation with floats and dials on both Korky and Fluidmaster. It requires additional installation efforts and man-hours without noticeable difference in savings over life of the flapper. Korky dials have poor quality inspection before shipping to retail distribution. You are at risk of purchasing a flapper where you cannot turn the dials by hand and must use tools in order to adjust dials settings.
Attach chain to hole on flush lever most directly above the flapper and adjust the chain length for minimal slack.