Taking a few minutes each week to maintain and monitor aquarium conditions is the key to a healthy aquarium. The FRESHWATER MASTER TEST KIT tests the parameters that affect the health of freshwater fish: pH, High Range pH, Ammonia, Nitrite and Nitrate. The FRESHWATER MASTER TEST KIT is highly accurate and economical. For ease of use, it comes with 4 glass test tubes with snap-tight caps & a convenient holding tray. The kit also includes a complete, step-by-step instruction booklet with computer calibrated color chart which provides information on how to correct unsafe water conditions.