Biofouling and sediment loads are the dominant factors that degrade and limit data quality. These factors can overwhelm inadequately protected sensors and invalidate their data—often in just a few days. Effective long term monitoring demands the highest data quality over weeks and months. The key to cost effective data collection requires a sensor package that can withstand the environmental hazards of coastal waters. The WQMx employs active flow control, passive flow prevention, light-blocking, active biocide injection and passive inhibitors to effectively and safely combat internal and external fouling. With fouling minimized, the superior inherent stability of the WQMx sensors translates directly to superior long-term data quality.