residential pool owner finding metal parts

by B. Fisher
(Export, PA)

I have been finding small ringlets of metal in the bottom of my pool. The pool is 20 years old. This is our first year owning and using Dolphin Maytronics M3. Do you have any idea what these could be?

ADMIN REPLY: If the parts are from the Dolphin Pool Cleaner, they could be from the bearings that drive the treads.