The SCI 301 Puzzler

A homeowner wishes to conserve water by placing a brick in the tank of his toilet. He places it at the bottom of the tank. The toilet flap valve is designed to close when the water level reaches a point just above the top of the brick. (It does this regardless of whatever else is in the tank.)

A neighbor claims that this will not conserve water and that the brick should be hung from the side as shown, with the brick well above the bottom. Who is correct, or does it make any difference?

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