Test strips are useless and unreliable. Around here, we refer to them as goofy strips. As we recommended to you back in an earlier post on 6/12, you need to get a good kit.

8 lbs. of CYA in 20,000 gallons would have added 50ppm. Do NOT add any more. Also do not use any more dichlor shock or trichlor tabs as they also contain CYA in them.