I just returned from vacation and my salt level showed “very low” so I added salt as I usually do. Within a couple hours the level read “very high”. Several hours later, the meter stated “very low salt” again with a “no cell power” message. I checked my salt cell and it had some build-up so I cleaned it thoroughly but neither message disappeared. I do not know the age of the cell as I have only lived here for 3 years but the pool was built in 2010. I’ve researched in the Hayward manual and can’t figure out what to do. I have a TCell940 but my system shows a TCell15 chosen. I don’t have any cables to check voltage of wires but I was wondering if it might just be time to replace the cell, thus the messages? And if I replace it, what do I replace it with: a 15 or 940?