Drain problems on PD can be related to many things, including constipation, catheter migration to where it is not near the rectum, clogging of the catheter with fibrin and/or wrapping of the catheter with omental tissue. Here’s an article that discusses some of these things that you might discuss with your home training nurse and/or nephrologist. Management of the Poorly Draining Peritoneal Dialysis Catheter - PMC
There are many posts about low or slow drains in the Home Dialysis Central Forums. You can use the search to see what has been suggested. Here’s one thread that a PD nurse responded to.