I bought my K-2006 in 2014 and it's been great. I did notice maybe a year or two ago that my 9191 dispenser bottle got dark. It happened suddenly and made it difficult to use. I always rinse it out as far as I recall and never use it for anything other than the CYA test. Maybe I forgot to rinse one time?
It's not a big deal as they are inexpensive to replace, I was just curious what that was all about.
It's not a big deal as they are inexpensive to replace, I was just curious what that was all about.