The aquarium pump sometimes gets stuck and stops and doesn't want to run when the power goes out, this can be caused because the pump is too dirty so the propeller doesn't want to spin.
Another problem will arise if when you disassemble the propeller and magnet parts, there are parts that are missing or fall into the water so that your pump cannot run perfectly anymore. Usually it is the part connected to the magnetic shaft that falls out when the cover is opened.
Here is a video where we can make our own parts to deal with an aquarium pump that tends to jam.
