This post is for my Mother's Pool. I found out from her that last season she used Pristine Blue instead of chlorine for a cheeper alternative. After much reading and educating her that Pristine Blue is not a sanitizer, but just an algicide, she will be making the switch back.
I wouldn't think she would need to drain any of the water for removal of Pristine Blue, just start BBB method as backwashing will slowly reduce the level that may be present. I already have her onto a good test kit TF100.
I am more curious if she may encounter cloudy water as she begins chlorine sanitation again, considering that last season she has had many bathers and I am sure a buildup of organics that will still be lurking. She is still winterized and has not opened as she is in Michigan. She has an 19,000 gal round AGP.
Any experience with this? I just want to give her an idea of what she may expect.