Originally Posted by Julie Stuva
my rena filstar xp2 started making a horribly loud grinding noise. any suggestions how to make it stop
I had some noise in my XP2 also. It was an air leak.
I went to Planetrena.com and sent them an email. They have a FAQ section that is great and also have reps to help fix the problem.
Like the others have said, it's probably in the impeller area.
Refer to this post:
Rena SP2 pumping bubbles