Description This CO2fish tank test indicator solution is a convenient tool for testing fish tanks. With its precision and accuracy, this test kit helps maintain clean and healthy water conditions for your aquatic pets. It is easy to use, simply add the reagent to the water sample and get accurate results. Features -Color:As Shown-Material:methyl blue-Size:7.70X2.10X2.10cm/3.03X0.83X0.83in-Note: 15ml,no need to mix with tank water;Green: right balance of CO2; yellow: too much CO2; blue: too little CO2 -The high precision testing kit can accurately measure the water quality indicators to help you keep the water quality of your aquarium clean. -Suitable for monitoring of fish tank, swimming pools, differentwater sources, widelyuse. -Thisindicator solution hashigh precision, can give you convenience to use in your daily life to test. -Light weight and easy to carry. Keep you informed of water quality of your fish tank water. -High definition displays the test results for an easy and accurate color change, very convenient. Packing list: 1 x bottle of indicator solution