Dolphin Oasis missing spots

[abfab]

The past couple of years I've noticed that my Dolphin Oasis Z5 doesn't seem to sweep up all the debris and will leave streaks. I tried brushing beforehand to loosen dirt but made no difference. When I look at the rollers they seem okay but I'm not sure what I should be looking for. It has no issue climbing walls. Liner is about 20 years old and extremely faded. After cleaning I store it in the shed and move it indoors during the winter.

Other than cleaning the propeller on top I have never serviced it. Is there maintenance that I should be doing such as replacing the foam parts or the enitre roller? It only came with one set of rollers - the one with the brushes.

 

[mknauss]

My Dolphin robot cleans everything every time. So something is not right.
How old is the robot?

 

[abfab]

My Dolphin robot cleans everything every time. So something is not right.
How old is the robot?

7 years old.

 

[mknauss]

Could be worn brushes. Does it have a filter or filter bag? Have you replaced those?

Probably approaching the end of its life cycle.

 

[abfab]

It came with mesh filters which I rarely use as our pool opens with little debris. I still use the original accordion filters and use a hose to wash them after each use.
How can I tell if brushes are worn? Our swim season is about 4 months.
Given the price point shouldn't these last for 10+ years??