It is not possible to know the condition of pond water without testing it. Regular water testing is the only way to protect the health of all pond life from deteriorating water conditions. So, test - don't guess. The API POND MASTER TEST KIT is the easy and accurate way to test pond water quality. This kit measures the 4 key water parameters: pH, ammonia, nitrite, and phosphate. Includes 6 bottles of liquid test reagent, computer-calibrated, laminated color cards, 4 glass test tubes with snap-tight caps, holding tray, as well as a complete, step-by-step instruction booklet, including information on how to correct unsafe water.