my pool was stable at 2ppm free and total chlorine and 60 ppm cyn, 7 .4 ph. I added 1 gallon of liquid bleach and the chlorine went to near 0, I balanced the ph with borax when i opened the pool this year.

Can anyone tell me why or how the chlorine may have gone to 0, I just added 2 lbs of hth super shock and my site glass ph/cl says I have about 1.0 ppm.