Just got the Tf-100 in the mail today:
CYA: Almost 90
Just bought the house (and the pool). The plaster has some brown stuff on it. Did the vitamin C test and it does clear up - trichlor test does nothing. Already did a 30% water change to lower CYA (prior to this test!).
My thoughts are:
1) Another water change to lower CYA
2) SLAM pool until OCLT passes
3) Balance the PH out with dry acid
Does this sound reasonable or should I approach this differently?