Review on 🐠 Pawfly Plastic One Way Non-Return Check Valve for Aquarium Air Pump by Crystal Long

The first picture shows what happens when the check valve is not connected and the air pump is in the floor. The second picture shows that the check valve is working properly. When the check valve is installed, water will not leak out. Figures 3 and 4 show the airflow with and without the check valve. You're trying to figure out what's what. 😃 In summary, all these reviews that these valves don't work and there is no airflow are all lies. The only thing you have to do when there is no flow is take a paper clip and use it to gently pry open the stuck 🛑 in the valve.