Specifically designed to measure and monitor the salt concentration in koi ponds. Salt is a factor in algae growth, plant health, detoxifying nitrite, and the elimination of most parasites. Very accurate and easy to use, simply turn it on and dip it into the pond. Within two seconds, the LCD displays the salt concentration measured in percentage. Ideal for checking the salt level in fish hospital tanks, koi ponds and tropical fish aquariums. Measures accurately from .01% to 1%.