Sight Gauge

I quickly found out I had no way to determine if the CO2 reactor was still producing gas so I made a sight gauge out of a salsa jar.

Drip irrigation fittings are the same size as aquarium tubing so I drilled two holes in the lid of the salsa jar and screwed two drip irrigation fittings into a plastic tube. One tube is longer than the other.

Install a check valve from an aquarium store between the CO2 reactor and the air pump or the air pressure will push the water in the sight glass back into the CO reactor.

Fill the jar 1/2 with water and screw the lid back on. Once the CO2 reactor begins producing gas, bubbles will appear at the bottom of the tube under the water. This is the CO2 gas. It will accumulate in the glass and then exit through the second shorter tube. Connect the output with aquarium tubing to a tee fittings between your aquarium pump and your algae samples. As the aquarium pump pushes O2 to each of the containers it will pick up the CO2 gas and distribute it a well.