Hi,

To adjust the float you have to try by bending the arm ever so slightly until the water shuts off on its own. You don't have to bend it too far, it won't get enough water. If this doesn't do the trick you need to get an evaporative cooler float from your local hardware store, they can best tell you how to change it because you will have it visually in hand.
Let us know if you want something more else please accept the suggestion.

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