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The purpose of this study was to evaluate the optimum environmental condition required for reaching the maximum growth rate of <i>P. parvum</i>. Eight ions (Na⁺, K⁺, CO₃²⁻, HCO₃⁻, Ca²⁺, Mg²⁺, Cl⁻, and SO₄²⁻) were divided into two groups with a uniform design of 4 factors and 10 levels. The results showed a rising trend in growth rate with increasing ion concentrations. However, concentrations that exceeded the threshold led to a slowdown in the growth rate. Therefore, adequate supply of ion concentrations promoted growth of <i>P. parvum</i>, whereas excessively abundant or deficient ion concentrations inhibited its growth rate. Specifically, the order of impact of the first four ion factors on the growth rate was Na⁺ > HCO₃⁻ > K⁺ > CO₃²⁻. The growth rate of <i>P. parvum</i> reached the maximum theoretical 0.999 when the concentrations of Na⁺, K⁺, CO₃²⁻, and HCO³⁻ ions were 397.98, 11.60, 3.37, and 33.31 mg/L, respectively. This theoretical growth maximum was inferred from the experimental results obtained in this study. For other ion factors, SO₄²⁻ had the most influence on the growth rate of <i>P. parvum</i>, followed by Mg²⁺, Ca²⁺, and Cl⁻ ions. The growth rate of <i>P. parvum</i> reached the maximum theoretical value of 0.945 when the concentrations of Ca²⁺, Mg²⁺, Cl⁻, and SO₄²⁻ ions were 11.52, 32.95, 326.29, and 377.31 mg/L, respectively. The findings presented in this study add to our understanding of the growth conditions of <i>P. parvum</i> and provide a theoretical basis for dealing with the water bloom it produces in order to control and utilize it.