If you believe that the solution you are using contains chlorine and yet after testing it with chlorine test paper, the strip is still white, you may be seeing what is referred to as the “bleaching out effect.” At high concentrations of bleach, the available chlorine will overwhelm the indicators used in the strips. If this happens, instead of developing a purple color, the strip will very quickly turn to white. The best indicator of this effect is the presence of a thin blue line on the strip separating the wet portion from the dry portion of the strip.