The AquaSource toilet is a high-efficiency toilet model sold by Lowe's. It has an elongated seat and a squat tank. Although the toilet has an interesting appearance, the parts inside are standard. A handle trips the flapper, which releases water from the toilet, then the fill valve refills the tank with water. If the water level is too high or low in the tank, you can adjust the water fill level by tweaking the fill valve.
Turn off the water supply to the toilet at the fill valve coming out of the wall. Turn the handle clockwise to turn off the water supply.
Lift up on the tank lid and remove it from the toilet.
Press down on the spring clip on the side of the fill valve float to release the float from the metal rod to which it is attached.
Slide the fill valve up or down to adjust where the final water level will be. Release the spring clip once the float is in place.
Turn on the water and test the float. Make further adjustments, if necessary.