I have had our pool for about 19 years and the KK is older than that. It serve me well until recently ... the last 3-4 years. I am not sure but it may correlate with the new 3/4 hp Hayward (20K gallon pool). Last year the pool tech was in the neighbourhood and he looked at my KK that would not move. He thought that the KK looked ok. He threw the KK into the pool and away it went to my amazement (10 ft/min) as it did in the old days. The pool tech observed that a hose was leaking. When we replaced the hose the KK stopped. After he left I put back the hose with the air leak and I was back in business. Since then I have been using the a leaky hose. It is very finicky of course. Too much leak and the suction drops ... so I have to "adjust" the leak to make it work at optimum. What is my problem? The suction is so strong that it is ridiculously difficult to pull the hose out of the skimmer at full suction.