SJE Rhombus TANK ALERT® AB Alarm Installation instructions This alarm system monitors liquid levels in lift pump chambers, sump pump basins, holding tanks, sewage, agricultural, and other water applications. The Tank Alert” AB indoor alarm system can serve as a high or [ow level alarm depending on the float switch model used. The alarm horn sounds when a potentially threatening liquid level condition centaurs. The hom can be fumed off, but the alarm light remains on until the condition is remedied.