Powersweep 228 grinding question

[deeze]

I have two powersweeps on either side of my aquarium creating a current and their power swaps and runs in 30 minute intervals. However, sometimes they make a terrible grinding sound for a second to two when they start (1 out of 2 starts). It sounds like the motor or impeller. Has anyone else had this problem and know a fix? They are being controlled by a ReefKeeper. The pumps are brand new.
Thanks,

 

[acrylic51]

Honestly can't tell you what the grinding noise is, but will tell you after they've been in the tank awhile and the coraline gets to them they will basically be useless and stop sweeping altogether

 

[calylove]

These are real easy to take apart and clean. Its hard to explain but theres a little pin inside that rotates in a groove that creates the "sweep" Mine will once in awhile start kind of sticking to one side. I just take it apart and clean and its good as new.

 

[traib]

I've been running a power sweep for over a year. Its covered with coraline algae and runs great. Once in a while the sweep sticks do to fine sand ingestion. I just tap the arm with a piece of plastic tubing and it starts sweeping as usual.