I have a Doheny Dolphin that is at least five years old and I bought it refurbished. It has always worked well but now it doesn't seem to be getting the pool as clean as usual. It is still getting the large debris and most of the silt but not all of the silt/sediment. We are using the folded corrugated looking filters for fine sediment. Could it be that it is coming to the end of it's life cycle (not sure how long they last)? The "flaps" on the bottom of the robot are mostly worn away (see photo), would it help to get those replaced and is it something I can do myself? The rollers and impeller appear to be fine. Thank you.