To adjust the water level in a toilet with a Max Performance Pro Grade Fill Valve, you can follow these general steps: 1. Turn off the water supply to your toilet. 2. Flush the toilet to empty the tank. 3. Remove the toilet tank lid and set it aside. 4. Locate the adjustment screw or float rod on the fill valve. 5. Use a flathead screwdriver to turn the adjustment screw: •Clockwise to lower the water level. • Counterclockwise to raise the water level. 1. Adjust until the water level matches the marked line inside the tank. 2. Turn on the water supply and flush to test the new water level.