Anyone know, my google fu can't seem to come up with an answer and most places seem to want you to by the cover just to get an o ring, which is kind of annoying.
I have always just ordered a new face plate when the o ring fails as one of the few pumps this an option for, also the most likely place it fails. My setup is heavy on debris in my pond, so my replacement schedule is not typical when there are no branches falling in your reef. But tend to replace a faceplate annually and an impeller biannually. I get 5-10 years out of each pump body this way.