ya, the 1 may work ok in the fuge, it definately isn't going to do anything in your 75G. I have a 2 in my tank and it only moves water about 8" out.. so with a 1 your looking at probably 5-6" of water push.. in a 75G tank, that isn't much.
The 1 would be perfect for putting in a trash can when mixing salt though.
The 1 would be perfect for putting in a trash can when mixing salt though.