The Markland Model 10B sludge gun can detect extremely light sludges and flocs found in drinking water plants and some processes. It is used to easily find sludge levels in lagoons, ponds, clarifiers or any other process where there is a sludge/liquid interface. An audible tone indicates sludge level. The design is portable, rugged and weatherproof. Sensitivity is adjustable for thick or thin sludges.