I have two test kits that are giving me completely different readings on TA. My pH is consistent at 7.5 for both kits. One kit is a new TF-100 refill plus the old one from last year are both giving me a reading of 110. My pool guy's test kit that I currently have is different. Instructions say 1 drop of chlorine neutralizer, 1 drop of a blue indicator, and then 1 drop at a time of the third thing to get the result. With that test I'm getting a result of 60. With the sample he took to the shop, he says he got a result of 60.
Full set of results with the TF-100: pH 7.5, TA 110, FC 3-4, cya 70
I'm using a sand filter and SWG, but there is also a portable DE filter set up (long story). I'm not familiar with DE filters but can't imagine this causing a problem.