Septic Drainer drainfield restorative from RCS II is designed to repair the soil in a septic drainfield damaged by hardpan soil issues. Due to restricted airflow, this hardpan soil layer causes aerobic bacteria to die off. Only anaerobic bacteria can survive without air. Anaerobic bacteria produce a waste product called biomat, which compounds drainfield failure. The solution is designed to remove the bond between sodium and the soil, which creates hardpan. The manufacturer recommends using it first to solve underlying hardpan issues, then add an oxygenator or aerobic bacteria to speed up the restoration process. 518/812-0000; www.septicdrainer.com.