I've been having drain line clogging issues on my new aluminum A/C coil. No problem with the old copper coil of the air conditioner. This is a common problem and the air conditioning service company advised me to run chlorine through the drain line monthly to keep it clean between their 6 month service. I decided to try the tablet on my 5t device. I had a biannual setup this morning and watched what happened as they cleaned the drain. I was shocked (as was the technician). The line was clear. In fact, only a few flakes of sediment remain from the past. So this pill not only prevented the line from clogging, but also cleaned the line. myself. Highly recommended.