This kit measures the most important aquarium levels quickly and accurately. The added benefits are being able to test pH, High Range pH, Ammonia, Nitrite & Nitrate while also being scientifically accurate for professional results. Follow API Easy Care Guide and use the freshwater master kit during regular care and when addressing water problem solving issues. 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 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.