Recently I've notice my sump pump discharge line making a gurgling sound, kind of like when you pour soda out of a 2 liter bottle. I took out the sump pump and tested it in a bucket of water with and without the check valve attached. It works, though I'm not sure how far water should spray up out of the pipe. There was no clogging anywhere on it. There is an anti-airlock hole drilled so that isn't it. It used to spray water like crazy out of the discharge line when on but now it just gurgles out the line. Any ideas? Nothing has changed with the whole plumbing of the piping.