Can I do the DPD-FAS chlorine test in my magnetic stirrer? I have the original PS233 from PoolSolutions (don't worry--I update reagents occasionally) and it came with 2 Taylor sample tubes, one of them clearly marked "Chlorine test only." My stirrer is not the Taylor one but has a glass beaker and a plastic-coated stirrer. Is there a contamination issue or something? I have always wondered about this and it's the only drop test I am still mechanically swirling all these years.
Also, which reagents and indicators "go bad" more quickly?