3701-31-04(D)(6)(a)(2) / Pool free chlorine disinfectant residual shall be above 1 ppm.
Critical Pool free chlorine disinfectant residual was below 1 ppm. Observed disinfectant residual to be ~0.75 ppm.
Do not operate the pool until the chlorine disinfectant residual is at 1 ppm or above. Adjust disinfectant residual to be within acceptable range.