A couple things. Mine stopped the other day and I cleaned it along with the magnet. Make sure you clean the housing where the magnet resides. In mine, I noticed the magnet was split and found out it was due to overheating usually from a lack of water. I bought mine used so I am not sure it had been run dry or what. With the split magnet, it caused the housing to get scared causing lots of bubbles and got worse. I could have replaced the magnet but a new pump was only a few dollars more so I did the new pump and it works better. Mine was a turbofloater multi 100. Like the skimmer. Bottom line check the magnet and blades on the magnet very closely along with the housing. Probably where you are going to find the problem.
Joe