try a vinegar bath first to potentially break up anything in the pump. As you pull it out to clean it though look at the props as if any of them have chipped a blade and that catches it is enough to stop the unit.
If you have the 130 I HIGHLY recommend the new rugged props and if you have the 150 they are coming for that shortly.
When the red light happened to me was after a power outage where a dwarf cerith crawled into my pump and when it restarted it broke a blade. I swapped out the paddles and was good to go.