Here's the story: Replaced filter this year because old one died. Started chlorinator and immediately got codes 172/185. After much online research (thank you all) we replaced the sensor. All the while, our local pool store told us to shock every five days so the water wouldn't turn green so we did. The sensor was replaced yesterday and no codes. We took a water sample up to the store and everything was okay enough to shock. We shocked it and then put the system to boost so that it would produce at 100%. Last night, of course, the chlorine was through the roof because we shocked it. The system was reading on and intermittently you could see the cell resting, reversing and on. This evening (24 hours later) we checked the water and 0 chlorine. Yep - zero.
We are so thoroughly frustrated. What should we do at this point?
Before we installed a new sensor, we also took a look at the cell and it looked fine but we cleaned it anyway (no foaming). Our pool is about 4 years old. 20,000 gallons. Never had a single problem until this year.
What do you all suggest?