Maintaining good water quality is the key to successful fishkeeping. The API Saltwater Master Test Kit is a complete kit for testing saltwater aquariums to protect marine fish and invertebrates from unsafe water conditions. The Saltwater Master Test Kit tests 4 key salt water parameters. The SALTWATER 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.