Cocrete finishers accidently got concrete in the skimmer box of my pool & the plumber failed to seal off the 2 inch pipe leading to the skimmer box. Does anyone know of a chemical that would help break up the concrete in the PVC pipe and not harm the PVC pipe. I was told that car anti-freeze may work. I have tried using a 3/8 inch pipe snake to lossen the conrete, but it tends to bind the snake up more than it can effectively remove the concrete. I want to leave cutting out the concrete sidewalk around the skimmer box as a last resort.