Sump Pump Not Draining Well?

I grew up with a sump pump in the basement and it would often get slow or stop completely. We could hear it go on and off, again and again. But that was when we knew that a plumber was the only answer.
The pumps can be blocked by a lot of things, including roots from plants and trees. Having watched the plumber, I would never tackle it alone. The thing was complicated and stinky!
If you have a friend that is a plumber, you can try bartering with him. Just don't wait until it quits completely.