I sealed with silicone and partitioned a 10 Gallon Aquarium with an 8 inch by 8 inch double glass plate with about 3 gallons on one side and 7 gallons on the other. The 3 gallon side was to be dry and filled with gravel and rocks, while the 7 gallon side would have a thin bottom layer of gravel and filled with water. After some time the water links over to the 3 gallon side until it is level with the water on the 7 gallon side. But when I drain the 7 gallon side of water the 3 gallon side does not leak over to the 7 gallon side and the water level does not drop. Any clues as to the 'why'? Because I don't have any and I'm baffled why the water doesn't leak back over to the 7 gallon side.