AquaClear 200 (now called 50)
Just thought I'd share my experience as it would have helped me to be able to find this theory online when I was googling for answers. I have an AquaClear 200 hang on the back filter and every now and then it runs dry and I have to pour water in it manually to get it started again. I'm not sure why it does this? I had this issue last week and no matter what I did I couldn't get it to restart. I cleaned the impeller unit really carefully. I tried the flicking it to start, pouring water in as it started and I tilted it to kick start it - this has worked in the past, I even tried vaseline, all to no avail. I could hear the motor trying and the impeller would spin part way but then stop. I eventually gave up and decided I needed a new impeller and/or shaft. I put it aside to order the parts online. Today I thought I'd have one more go to get it started and it fired up instantly. This is not the first time this has happened to me with it. My guess at this stage is that it has something to do with the 46 degrees celcius heatwave we were having (that's 114.8F). It's cooled down now and the pump worked instantly. Maybe someone else has had a similar experience? I was considering buying a new pump. I'm so glad I didn't.