Keep the depth reference and process context clear when reviewing Royce Aqua 22 checks.
A blanket reading identifies an interface at a particular place and time. Comparing two numbers becomes useful only when their reference, measuring point and operating conditions are understood.
This PMA worksheet helps organise secondary-clarifier checks and hand over a change for review. It complements the instrument instructions and the works’ approved procedures; it does not set an alarm level or prescribe a return-sludge adjustment.
State what each number means before plotting a trend or comparing tanks.
The Aqua 22 depth measurement is referenced to the liquid surface. At an unchanged surface level and measuring point, a smaller depth means the detected interface is nearer the surface.
A change in the water level also changes this reference. Record it rather than treating every depth change as movement of the sludge alone.
Blanket height above the floor is a different quantity. Derive it only if the actual water depth above the local floor at the measuring point is known and both measurements use compatible references.
Do not subtract a reading from a tank’s nominal maximum depth or compare a surface-referenced reading directly with an instrument reporting height above the floor.
At the same measuring point with the same water-surface level, interface depths of 2.4 m and 1.8 m place the second interface 0.6 m nearer the surface. These illustrative values do not establish the cause, a safe operating limit or a control action.
If the surface level or measuring point changed, reconcile the references before drawing that conclusion.
Keep the original observations alongside any interpreted result. Use the same agreed point codes on the instrument and the works record.
Confirm the point code, units, water-surface reference and sensor configuration. Where the site procedure permits, repeat at the agreed point and record the new observation without deleting the first.
If the change remains unexplained, share the records and sensor-check history with PMA rather than assigning a cause from one reading.
Use flow, loading, sludge-return history, effluent observations and the works’ established tests to investigate the process. A blanket-depth reading alone neither measures effluent suspended-solids concentration nor demonstrates discharge compliance.
MLSS concentration and a settlement test answer different questions. Keep their units, sampling times and methods explicit when reviewing them alongside the clarifier record.
Use the dedicated instrument guide for its measuring method. Bring the comparison record to PMA when discussing the application or an unexpected response.
Review the PMA product page for compatible measurement functions and application support.
The dedicated Portable Sludge Meter guide explains the depth reference and tank-side measurement routine.
Speak to the PMA team about your instruments, reagents or service requirements. Tell us what you need, and we’ll help you find the right next step.
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