Can I core a hole through the side of an old concrete/plaster pool to add a return line and get it properly sealed? The original pool was just a concrete hole in the ground, poured over 50 years ago. The bottom cracked and, in the 1970's, a new gunite pool was plumbed and installed inside the old one. After it was filled and operated, some areas were found to have poor circulation. The solution used was to add a return line in one end and a suction line in the other end, with both lines being run over the wall. If we cored the holes and put the lines below grade and into the pool, can such a job be properly sealed? One pool service guy told us we would never be able to keep it from leaking. Comments? Solutions? Ideas? All are welcome. Thanks, Hal