Here, we coupled successive rounds of molecular microbial methods (MMM) to calibrate adenosine triphosphate (ATP) readings to trend Halanaerobium fouling in unconventional wells. ATP was then used to drive a biocide efficacy study, which resulted in selecting a glutaraldehyde/quaternary amine (quat) blend. This selection was partly supported by literature searches, which showed that quats have been effective on Halanaerobium. ATP monitoring was then used to direct the success of a downhole biocide treatment program for horizontal wells. Since sessile samples were not routinely available, planktonic samples were used. Over two years of reviewing the treatment results of approximately 30 wells in a single lease, where multiple sample most treatments were successful in returning/or maintaining wells within KPIs. The operator has experienced reduced failures and currently relies on MMM supported ATP to monitor multiple leases where Halanaerobium is present.