Ugh I am about fed up. I got a 30g wet/dry sump tank. My main sump pump is a rio 20hf. When it works it pumps about 900gph. The problem I have is that whether i lose power or i shut off the pump for tank maintance, when it is turned back on the pump doesn't want to work. I can hear it hum but the impeller will not work. I can put this pump in a 5g bucket of water and get it to work. I have a back up thats a different brand (surge 6000) and it will do the same thing from time to time. I am doing something wrong or something or is there a trick to get these submersible pumps to work consistancely? Or maybe the pumps I have are just cheap pieces of ****. I don't know. What i do know is that i am afraid to shut the pump off cause i might not get it to run again like now. It would be nice to have pump that i could rely on consistance basis!