Your break is to close to the base for repair. I would'nt trust any repair made to the U V. This is on the press. side or discharge of the pump. With a 300 gal. tank you probally moving a good amount of gph. I'd hate to run out for the night and come back to an empty tank, dead fish and water damage to my house. I would see if the base could be replaced or buy new. No plumber, but I am a Steamfitter Local 602.