A big Thank You to Pool Clown!! I was getting the 172, 185 and 186 error codes and had no idea what to do. (we just bought the house) After reading this thread I followed Pool Clowns advise and purchased a new flow/salt sensor. (online at Aqua Superstore for $174.00) TA DA...everything is great now!
By the way when I asked my local pool company for assistance they wanted to sell me a whole new salt system...said I would need it. I won't be going back to them anytime soon!