A drain line from the side of my pool cracked right where it comes out of the concrete shell. My plumber has chipped away about as much concrete as we think is prudent to try to get a new coupling on the pipe. That repair still has a slow leak and I dont want to chip down any more to cut the pipe and try again. Are there any tricks for repairing such a pipe. I was thinking about trying to make a coupling that could slide inside the problem joint. Does such a thing already exist? Thanks