I did a bleach shock treatment on our pool about three weeks ago and the water was clear with no visible signs algae. When performing the shock the FC was holding at 23 at night so I let the FC level drop to 11 then the algae slowly started to return. As of last night my FC did not drop from 23 but I can still see some algae on the bottom and around the return jet. Why does the algae keep returning is there something that I am doing wrong? I don't know if this is normal but every since I raised the shock level my TA sample will turn from green to yellow instead of red.
My numbers are
TA about 120 sample turns yellow instead of red