Portable sludge level detector – the Sludge Gun®

Portable Sludge Depth Meter

The Markland Advantage

Simplify operators’ day-to-day tasks

  • Check sludge interface levels with this simple-to-use device. Press the trigger and lower the probe – a loudspeaker on the Sludge Gun® howls when the probe enters the sludge.

Quickly determine sludge blanket levels

  • Obtain sludge depth readings from numbered markers on the cable.

Assess variable concentrations within the sludge blanket

  • Locate the true settled sludge blanket interface level, as well as the overlying unsettled sludge blanket. Pitch and volume of sound varies depending upon concentration.

Facilitate operator safety during sludge level spot-checks

  • Compact construction provides ease of use on narrow catwalks or from boats in lagoons.

Ensure low maintenance costs

  • Rugged and reliable – a proven track record!

Get answers when you have questions

  • Technical assistance is direct from the designers and manufacturers.


Used wherever solids are separated from liquids:

  • Municipal water and Wastewater Treatment Plants
  • Primary and Secondary Clarifiers
  • Dissolved Air Flotation (DAF) Tanks/Thickeners
  • Industrial Process and Wastewater Clarification
  • Wastewater Lagoons
  • Tailing Ponds
  • Farm Lagoons
  • Septic Tanks
  • Settlement Lagoons


  • simple, light-weight, one-hand operation (even when wearing gloves)
  • self-storing cable spool – no tangles
  • usable at night – no dials to read
  • weatherproof case – usable in rain
  • spring-loaded trigger turns off gun – can’t leave on and drain battery
  • standard AA batteries, easy to replace, and last about one year
  • adjustable sensitivity control – easy to adjust for thick or thin sludges
  • variable pitch note, according to sludge density
  • does not require calibration

How it Works

Markland’s popular Portable Sludge Blanket Level Detector – the Sludge Gun® makes everyone an expert at sludge level interface detection.Portable sludge blanket level detector

When the trigger is depressed, an LED transmits bursts of infrared light, across a probe gap, which contains either liquid or sludge. The beam is received by a phototransistor on the other side of the gap. If the gap contains air or clear liquid, nothing happens. However, when suspended solids are encountered in the gap, some beam energy is absorbed and the rear-facing loudspeaker, on the butt of the gun, starts to howl. As the percentage of solids content increases, both the pitch and volume of the sound increase, which gives the operator a clear indication of where the thickest sludge is located. By holding the trigger and listening to the note, while slowly moving the probe up and down, the operator can observe the depth markers on the cable and establish the location of both the sludge blanket and the overlying unsettled layer/cloud.

After use, the cable is wound on the self-storing spool at the front of the gun. The one hand, one piece, Sludge Gun® detector is easy for an operator to carry from tank to tank. Use it in the rain or snow, day or night. This rugged tool is a valuable addition to any plant.

Markland also offers Fixed Installation Sludge Depth Meters, which automate desludging or function as intelligent sensors for your computer or PLC.

Technical Specifications

Weight 2 Kg (4¼ Lbs.)
Batteries Six Alkaline Pencells
Battery Life One Year (Normal Service)
Materials Probe: PVC & EpoxyCable: Vinyl JacketedGun: PVC & Aluminum
Operating Temperature Minus 20°C (0°F) to 50°C (120°F)
Loudspeaker 3 Watts, Weatherproof Type
Printed Circuit Board Epoxy-Glass, Moisture Sealed, Plug-in Style
Sensivity Control Trip point can be adjusted from barely cloudy water, right up to the thickest sludge
Cable Length 10 Meters (33 Feet)
Cable Markers Self Adhesive Vinyl (Numbers 1 to 30)(Shipped loose for customer installation at either foot or meter readings)


This animation shows how simple it is to operate Markland’s Portable Sludge Level Control Equipment: Press the Sludge Gun® trigger and lower the probe.  A loudspeaker on the butt of the gun howls when the probe enters the sludge.  The pitch and volume will vary depending upon the sludge blanket concentration so the unsettled portion above the blanket can also be detected.  Read the sludge depth from the numbered markers on the cable.

Interface Level Detection

To receive a quote for a Markland Portable Sludge Level Detector – The Sludge Gun®, please complete the form found below.

Contact Information

Please let us know how you heard about Markland Specialty Engineering.
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Your Requirements

Sludge: mg/L Color:
Overflow Liquid: mg/L Color:
Note: Describe colour, i.e. pale gingerale, dark brown, water clear, milk, etc.

Temperature: °C°F
Sewage, PrimarySewage, Secondary
Industrial Sludge - List Major Components:
Liquid is waterOther - List major chemicals:

How many instruments are required?

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