Sorry it's been crazy here- yes they came out said it was dirt that adhered to the pebble. He poured some acid in and brushed it off. He was totally rude about it said it wasn't a warranty call and was our fault and we will have to deal with our pb to see if they want to charge us for what he did. which is funny because he never asked if I wanted him to fix it and did not tell me this was going to be a warranty issue till after he was done. The places where there is pebble missing they are going to fix. I guess therye sending out a diver to go under and do it with water still in the pool.