I'm trying to adjust water level above scum / calcium white line. The paralevel float has markings to raise with an arrow pointing and lower with arrow pointing opposite direction. Problem is the float is already turned to the top of shaft, and water level in pool is dead center of tiles which is 3/4 inch below white line. How can I get the water level higher? Also when I add water with hose after a few days it's back to center of tile again.