I've had a pure freedom trolley for just over a year now. I used to have the speed on about 15-20. The past few weeks I've gradually had to up the speed, first to like 18, 20, 22, etc. today I had to have it on 40 to get the required speed otherwise the water just trickled out. I've read before somewhere about debris getting in to the pump. Does anyone think this could be the problem? Or any ideas what the problem is and how could I solve it?