Check the listing for details. Red Sea CO2 Reactor 200 Micro Bubble Diffuser W/ Integrated Counter &Check Valve. Condition: New, Made in China. Listed at 40.00 USD. This Red Sea CO2 Reactor 200 is a high-quality Micro Bubble Diffuser that is perfect for use in fish and aquariums. It comes with an integrated counter and check valve, making it easy to use and maintain. The diffuser is designed to produce a large number of tiny bubbles that will help to increase the oxygen levels in your tank, making it easier for your fish to breathe. The Red Sea CO2 Reactor 200 is a great choice for anyone who is looking for a reliable and efficient way to improve the water quality in their tank. It is made from high-quality materials, ensuring that it will last for years to come. With its easy-to-use design and integrated counter and check valve, this diffuser is perfect for both novice and experienced aquarium owners.