How long have you had the torch? What do you have for fish? As Coleus suggested, one of them may have picked at it to death
I would hope that any LFS that you bring water to would be truthful about your water parameters.. If anything was out of wack they should have said something so I would almost give them the benefit of the doubt, but that might just be me being naive? You should still get yourself a set of test kits though.