I have a leak where my inner flange meets the ceramic title in my shower. I cut a hole in the ceiling below and can see where it's leaking. I don't think it's the liner. My question is what prouduct do you recommend to put between the flange and the title. I used a title grout repair type caluk and the leak has stop but the grout eventually start to wash away. Is there a prouduct that will hold up and not wash away?