If you can remove all (or nearly all) air from the top tank, you can draw it up without losing the water in the tank, so long as you don't pull it OUT of the water. You can do this with a cup and a big bowl. Fill the bowl, place the cup in sideways to remove the air. Invert the cup and lift. The water stays in the cup until you pull it clear above the water surface, correct? The air pressure pushing down on the surface of the water in the bowl supplies the pressure required to lift the water in the cup. Technically, you could lift a column of water 32 feet in the air this way. 1 atmosphere (14.7 psi), which is standard air pressure at sea level (at room temperature) is equal to the pressure beneath a column of water (at the room temperature) 32' high.