I have the G4 in my 18X36 gunite pool with DiamondBrite finish and after some adjustments made after the initial install by our pool builder, I can say that it works pretty well. Some have said that it only cleans the floor but mine not only climbs up the wall it will also works it's way across the wall. This might be due to the fact that my pool has a very smooth radius where the walls meet and where they meet the floor.