Ok I am pretty sure what is going on with these darn circles. I have a new client that I just picked up. I mow all of my lawns at 3" and mowed his 3 times at 3". He Ferted a week before I took over and has been growing at a rate of 5-6 inches a week. He wanted me to cut it shorter 2.5 inches so I did telling him that I didn't think it would look good and the whole 1/3d rule spiel. Any ways long story short. after mowing at 2.5" it seemed to leave circles in the turf where I emptied the bag and scalped several areas. All of my settings were right on and level but he seems to think that I did something wrong even though I told him I did not think it was wise to cut lower in the first place. My question is what do you guys think caused this? And how can I prevent it again. Knowing the 1/3d rule.