Another thought would be during your next water change use a strap wrench on the stand pipe for more leverage. Drying the pipe before the attempt will help.
Cove Beach - I thought about using a strap wrench but would need to buy one. The leak stopped so will tuck that idea away for future use and pick up a strap wrench when I'm next wandering through Harbor Freight.
120 Discus Show Tank / 125 Grow Out Tank / Fish Room (almost) Under Construction
[SIGPIC][/SIGPIC]