I am resealing a 300 gal I need black silicone and can only find GE II and not GE I but just read somewere that GE I is now the same as II they both have mildewcide. Do you really think this is not tank safe even if I flushed the tank then refilled I can't imagine once silicone is cured that the mildewcied can continue to leach out? Does anyone know were to get tank safe black silicone.