I need to get serious about chemical testing. I have seen the TF-100 mentioned several times. I have used test strips on occasion and the pool store testing. Getting ready to cover (not winterize) as soon as temperature gets down to 60. Also, the cell in the SWG is 6 years old. Seems to still be working. Should I just leave it alone until it fails? I assume I'll know that when chlorine stops generating? Thanks ahead of time for any help!