The Helios Phosphate Process Buoy measures phosphate through direct immersion in aeration basins or final effluent. The buoy is filled by the hydrostatic pressure of the water, and emptied by air pressure. This eliminates the need for pumps in the wastewater. Valves contact only air, reagents, and calibration standards, assuring a high level of reliability.

The Phosphate Buoy is equipped with a filtration cell, in which wastewater is separated from sludge and solids before it is fed into the reaction cell. During the phosphate measurement, a low volume of reagent is accurately regulated to assure high measuring accuracy with low reagent consumption. The buoy automatically calibrates itself daily using the standard addition method, and at the same time compensates for variability in the wastewater.