The invention relates to an aqueous solution prepared from purified water having a pH of 5.5 to 7.5, and osmolality of 200 to 400 mOsm/kg, a conductivity of 17 to 22.5 mS/cm at 25 °C, and prepared using 1 to 20% of filtered sea water, wherein said solution contains a potassium salt content of 90 to 180 mmol/L.