I would find another method to clamp the hose rather than putting metal in the tank. Stainless steel is not rust proof, it just takes longer to rust than regular steel. There are different grades/qualities of stainless of course and what you find at a hardware store is not that great. I've had a few start rusting/corroding just from the saltwater moisture in the air around a tank. You might look around online and find one made for use on boats or something like that for constant contact with saltwater.