ITEM NAME:Aquarium Carbon Dioxide CO2 Checker Tester Monitor PH Indicator Glass Drop Ball Store category Sign Up Now ! You may also like Aquarium Carbon Dioxide CO2 Monitor Glass Drop Ball Checker Tester PH Indicator Product Description Specifications Material: Glass Size : 3cm diameter. Suitable For: Long-term CO2 monitoring How to use 1.Will test agent about 15(or according to the actual amout) drops into the monitor, need not to add water 2.Change again every 30 days, airtight preservation at room temperature. Note Simply add couple drops of test solution and water into the checker. Stick the checker on the edge of the aquarium. Ensure water level cover the opening of the checker. Packing Included 1x Glass ball 1x Test solution Notice: 1.Please allow 1-4mm error due to manual measurement,Please make sure you do not mind before you.Aquarium Carbon Dioxide CO2 Monitor Glass Drop Ball Checker Tester PH Indicator. Stick the checker on the edge of the aquarium. Ensure water level cover the opening of the checker. 1x Glass ball. Material: Glass.