system from someone like Dupla, you are likely to spend about $300. That seems a bit pricey, doesn it?
2 tank at a local welding supply place and use it to bubble CO2 into the water. CO2 in the tank is under high pressure. A pressure regulator brings this pressure down to a manageable level, and ordinary aquarium air valves can be used to regulate the flow to individual aquariums. [Editor’s note: this is counter to general net-experience. Most of us end up installing a fine-metering needle valve after the normal regulator in order to regulate the flow down to a few bubbles per second, because normal aquarium air valves do not have good enough control.] The CO2 reactor is simply a small chamber that allows the CO2 to be dissolved in the water before it escapes into the air. Outflow from a filter or a pump enters the top of the reactor; CO2 is bubbled in from the bottom. To give the CO2 more time to dissolve, one can add a system of baffles to trap the gas as it is moving up. Near the top of the reactor, there should be a small hole to vent other gases, which may be present in small amoun
