I have the same pump, and sometimes after I do a water change, I would turn the pump back on and it would make that noise. but than I learned to just turn the pump off and let it back syphon for a couple seconds then turn it on and it's fine.
....and it is always is quiter when it is fully submerged with it sitting on a sponge
....and it is always is quiter when it is fully submerged with it sitting on a sponge
i don't know why... and i don't want it to come back... it has been running for 28 hrs already... would i still need to open it or just leave it as an inline?