I was starting to see a little green algae in my pool, Chlorine was around 3 (I usually run 4-6) and I told my pool guy. The next day he told me he added algaecide (I don't know what kind) and a gallon of Chlorine. Today, two days later, I was doing my routine testing and see that Chlorine is less than 1 on several different samples with different test kits, including FAS-DPD. I texted my pool guy and he said don't worry. the algaecide masks the chlorine test. It'll be fine. I've never heard that and can't find it referenced online. Information please? Thanks.