Totally painless installation. Tech had to leave for some parts, but got the job done just fine. I was still waiting for my tile guys to finish, so it was a week or so before pool was full so I could power this up. Easy to run, got used to doing a few new chemistry tests and using acid to reduce the pH. I am not fond of the manual, which seems to skip around a bit when it could be simpler, but this is really an easy sanitation system. Pool water has been sparkly blue - I just skim leaves and run my robot, test pH, copper and hardness weekly, adjust pH, switch to ionize for a day a week, and add a little shock after big rainstorms. A vast improvement over the bromine I used previously. Water is really nice now.