A HANNA Model HI 93750 Ion Specific Meter, Potassium provided results similar to those obtained by flame emission spectrophotometry for potassium concentrations in the range of 8–92 mg/L in low‐salinity water (2–10 ppt). Regression analyses of potassium concentrations performed using the two methods had correlation coefficients (r) of 0.999 for samples from ponds and 0.997 for a series of standards. In comparison with the flame emission method, the potassium meter achieved greater recovery of potassium spikes in one trial and equal recovery in a second trial. The relatively inexpensive meter is sufficiently precise and accurate for monitoring potassium concentration in low‐salinity water for pond aquaculture.