Dolphin robot scuffing up my fiberglass pool?

[tfpusername]

I’ve had a Dolphin Active20 for 3 years with no problems, but a few months ago I started noticing grey scuff marks on the sides of my pool (fiberglass). I’ve inspected the (also grey) treads/scrubbers, and they all seem to be intact (no rough/exposed plastic). I’m not sure what’s causing the marks on the walls, but it HAS to be the robot, right?




At first I just assumed the rubber was disintegrating over time (I sometimes leave the robot in the pool when not in use), but the residue doesn’t seem to come off with just a standard pool brush. The scuffs don’t really feel rough though… I talked to a guy at a fiberglass pool store, and he suggested I try a Magic Eraser, but I’m not expecting it to completely remove the marks...

I really loved having an automatic pool cleaner, but I’m a bit worried of causing more damage to the pool. I was looking at this one…

Amazon.com : PAXCESS Automatic Pool Cleaner, Robotic In-Ground/Above Ground Pool Cleaner with Wall Climbing Function, Large Filter Basket and Tangle-Free Cord Up to 50 Feet : Garden & Outdoor

Seems to have a different/smoother kind of scrubber… But I’m still a little nervous about buying another one of these. Have you ever heard of a pool robot causing these kinds of markings on fiberglass?

And other than insanely high Calcium Hardness, my chemicals are fine.

Any thoughts?

 

[tfpusername]

Well, still trying to decide if I should get another robot. This one looks exactly the same but 30 less...

Amazon.com : AIPER Automatic Robotic Pool Cleaner with Tangle-Free Swivel Cable, Large Filter Basket and Wall Climbing Function, Ideal for In-ground/Above Ground Swimming Pools up to 50 Feets : Garden & Outdoor

Amazon.com : AIPER Automatic Robotic Pool Cleaner with Tangle-Free Swivel Cable, Large Filter Basket and Wall Climbing Function, Ideal for In-ground/Above Ground Swimming Pools up to 50 Feets : Garden & Outdoor

www.amazon.com

Some of the reviews indicate it works fine on fiberglass, but still a little worried.

*to be clear, based on where the scuffs are, it looks like it happens when the robot is cleaning the tile line, and the treads are grinding on the pool wall (to keep it afloat). This AIPER looks like the treads (and the scrubber/roller) are a bit smaller/might be more gentle on the walls?