I called Taylor to ask how I know if their reagents are expired, and by using the lot numbers, they were just able to tell me what it is due to expire. Fortunately, everything I have here is good for another season, except the R-0002. I called one local pool store, and they have some Taylor there, but because they don't sell the small bottles, it's more than I want to pay for a single reagent. The thing is, according to http://www.taylortechnologies.com/Ch...SP?ContentID=2 it should be taking on colour to be expired, and the stuff is still clear. So I'm not totally sure what to think.