I found a few openings in the edges of two grids today while cleaning the filter. I was hoping for something less expensive but... Anyway I ordered the replacement set and started to remove the old one when I came to a stop at the pvc coupling that holds the manifold to the stand pipe. It will not turn... Either direction, and I do not want to break it. Does anyone know which way it should turn while looking down at the fitting? Any good ideas or suggestions on how to free it? I am soaking it now with PB Blaster in hopes it may free it up. I have had no luck with strap wrenches and have made some modifications to a oil filter wrench in hopes of better results. Any suggestions appreciated.