There is considerable interest in the detection of anionic nutrients due to their implication in eutrophication of ponds and lakes and increased incidences of harmful algal blooms. Controlling the release of these nutrients into the environment requires a sensor capable of monitoring them continuously, simultaneously, in real time, in-situ, and with little or no sample preparation. Such a sensor needs to be able to differentiate the ionic species, not suffer from interferences, be able to detect ppm concentrations of pollutants, and be reversible. One technology, which meets many of these criteria, is surface-enhanced Raman spectroscopy (SERS) of cationic-coated, silver substrates. In this communication, the response of cationic-coated, silver SERS substrates to anionic nutrients is characterized. The effects of substrate preparation and chloride ion are discussed as well as sensor design.