ITEM NAME:Aquarium Carbon Dioxide CO2 Monitor Glass Ball Drop Indicator Checker PH T3E9 Aquarium Carbon Dioxide CO2 Monitor Glass Drop Ball Checker Tester PH Indicator 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 Carbon Dioxide Detection Solution.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 Carbon Dioxide Detection Solution.