test error

Hi, just got a new 300 gal spa and first time owner. So, followed the pool store directions for water chemistry and all measures are within norms on the test strips, except free chlorine which goes back to 0 every day. So, every day for the last 5 days I have added about 1/2 TBSp of dichlor...

This page says to glance and not look for the black dot, but this page says to continue pouring until "all traces of the black dot at the bottom of the view tube completely disappears, even after you stare at it for several seconds." Which one is right?

error with CH test from TF-100