Water Quality Sensor Knowledge Base
Short, practical answers to the questions our engineering team gets asked most — calibration procedures, measurement units, technology trade-offs and parameter selection. Written by engineers who deploy these sensors in the field, not by a marketing department. No fluff, no reagent catalogs: just the technical reasoning you need before you buy or commission an instrument.
Calibration & measurement protocols
How to Calibrate an ORP Probe: Standards, Steps & Limits
ORP probes are verified, not slope-calibrated. Standards (Zobell, quinhydrone), step-by-step checks, acceptance tolerances and a troubleshooting table for platinum electrodes.
NTU vs FNU: Turbidity Units Compared (EPA 180.1 vs ISO 7027)
Same formazin anchor, different light sources. Where the readings diverge, which unit your market requires, and why you should never mix methods in one data set.
Optical vs Membrane Dissolved Oxygen Sensors
Flow dependence, consumables, unattended stability and total cost of ownership — a side-by-side comparison that ends with where each technology still makes sense.
COD vs BOD vs TOC: What Each Measures and When to Use It
Three organic load parameters, three different questions. Includes the BOD/COD biodegradability rule of thumb and why universal conversion factors mislead.
Parameter deep dives
Ammonia vs Ammonium (NH₃ vs NH₄⁺): Differences, Toxicity & Conversions
The pH-driven equilibrium, free ammonia calculation and why it decides toxicity in aquaculture and wastewater.
What Is a TDS Meter and How Does It Work?
Conductivity-based estimation, what it can and cannot tell you, and where a real EC/TDS sensor earns its keep.
Turbidity Sensor Guide
Ranges, mounting, fouling management and method selection from drinking water to sediment-heavy surface water.
Dissolved Oxygen Sensor Guide
Why luminescence replaced membranes in unattended monitoring, and how to keep DO data trustworthy.
TOC Analyzer: Complete Selection Guide
Oxidation technologies, NPOC vs TC, CO₂ detection methods and a full selection decision tree.
Application & selection guides
Water Quality Sensor Selection Guide
Parameter-by-parameter selection logic, from sensing technology to output and maintenance planning.
Wastewater Monitoring Applications
Where COD, BOD, DO and turbidity sensors fit across a treatment train, and what each stage needs.
Optical Water Sensors: Technology Overview
The optical product family at a glance — DO, turbidity, COD, nitrate and multi-parameter platforms.
Water Quality Sensor Cost: 5-Year TCO Compared
Consumables, labor and downtime broken down — where optical and electrochemical technologies diverge, plus a six-point quote-comparison checklist.
New pages are added continuously. If a question is missing, it is probably on our whiteboard already.
Have a question this list does not answer?
Send it to our engineering team — questions from the field become the next knowledge base page.