The KoiMedic Digital Salt Test Meter is specifically designed to measure and monitor the salinity levels for your Koi pond. The meter is very accurate and easy to use, simply turn it on and dip into the pond. Within two seconds, the LCD will display the salt concentration measured in "percentage". Koi Medic meter measures salt content which helps control algae growth, detoxifies Nitrite, and aids in eliminating parasites and the overall health of koi fish. Salt concentrations between 0.3% and 0.5%(3 to 5ppt) will upset the osmotic balance of some parasites i.e. the parasites' cells will dehydrate. Salt concentration of 0.3% are effective at detoxifying nitrite and concentration of 0.25% or higher has been used to control string algae. Nevertheless, salt can cause pond plant damage as the concentration increases. Floating plants (water hyacinth, water lettuce, etc.) are affected at lower concentrations than most bog plants. Needless to say, being able to precisely measure and control your salinity is an absolutely must for any Koi owner. Features: Operating Range : 0-10 PPT Accuracy: +/- 0.03% Battery Life: 150 hours Battery Type: 4 x 1.5V button cell (Alkaline A76 or equivalent) Automatic Temperature Compensation: 0 to 50°C or 32 to 122°F comes with a nice carrying case Packaging Dimension Size (LxWxH): 185mm x 65mm x 25mm Packaging Weight: Approx. 135gm Optional Accessories: SS0005N - CAL 0.5% / 5ppt Standard Salinity Calibration Solution - 90ml View KoiMedic Instruction Manual (PDF) Meter Reset: Press and hold Read and Cal button, then insert the battery. Display shows 25C follows by C00 then CAL At CAL, put meter in 5 ppt solution. Meter will Cal to 0.5, Meter is now reset Salinity Meter Reset Example