Can't resist pileing on.
I bought and fought with my Dolphin and Maytronics for two years. It got stuck everwhere and went back and forth and back and forth and back and forth ...................................
The final straw was I saw marks where the dolphin got stuck ---- It actually wore the color off the liner

I have replaced the dolphin with an Aquabot T-4 and don't know why I waited so long.

Send the dolphin back if you can!!!!!!!!!!!!!