I found out why my RIO pump stopped. A little story:
At my apartment complex, we have very unstable power. I ended up putting a UPS on my tank because of the power fluxes. Well, everytime the power does this, the pumps wind down and sometimes make a gurggling noise and start back up. One time, the RIO 800 that was on my Potien skimmer, did not start back up. I took it all apart and whoa to my surprise, a ceramic shaft. I found it in 4 peices. I went to the LFS, and another surprise, the replacement impellers come with metal shafts? I don't know, but it seems these ceramic shafts that RIO uses, must not be very stable and strong. When the pump turns back on, the torque must have snapped the shaft. I replaced the shaft with the metal one, and now,,,,no problems with restarts what so ever. I don't know if this sheds some ligth or not, but, it is my experience.....I will not buy another RIO pump as long as there are others out there. He he Logan,,,get a kick out of this?