Carbon Dioxide: Part Three, Installing a System

Pierce CO2 Starter Kit 95g - 7 pieces


by John Tullock

Our Up Aqua Carbon Dioxide System is the ideal choice for a small planted tank. Simple and easy to install, the system includes seven components:

  • CO2 cylinder (95 grams)
  • Stand for cylinder
  • Regulator with pressure gauge
  • Bubble counter
  • Check valve
  • Diffuser
  • Suction cup

In addition to these items, you will need several feet of CO2-safe tubing. The actual amount will depend upon how your aquarium is set up. For example, if you want to store the cylinder in a cabinet under the tank, you will need more tubing than if the cylinder sits on a shelf beside the tank. Your best bet is to measure the distances involved before you head for the aquarium store.

Being installation by deciding where in the aquarium you wish to locate the diffuser. It should be placed near the bottom of the tank, to facilitate dissolution of the CO2 into the water. Locate it in a corner or behind an object to keep it out of sight, but choose a spot where you can easily remove it later for cleaning as required. Thread the flexible tubing through the tab on the suction cup, and attach the diffuser. Lower the diffuser into the water and press the suction cup to the glass to hold it in place.

Hold the bubble counter under water until it fills to the “water line” mark. Next, using its suction cup, attach the bubble counter to the outside of the aquarium in a convenient spot. The tubing from the diffuser attaches to the side of the bubble counter that DOES NOT have a rigid tube projecting inside the counter.

Attach a length of tubing to the other side of the bubble counter, the one with the rigid tubing projecting inside.

Connect this tubing to the side of the check valve marked “OUT.”

Carefully screw the regulator on to the CO2 cylinder, after first making sure the valve is in the “OFF” position.

Finally, attach tubing from the outlet of the regulator to the unconnected side of the check valve. Place the cylinder in its stand and set it near the aquarium. When you are finished, the set-up should look like the schematic below:

Up Aqua Carbon Dioxide System

Carefully open the regulator valve a small amount. You will immediately see bubbles in the counter. Close the valve until the gas barely escapes. Recommendations range from one bubble every 3 minutes to one bubble every 30 seconds. The optimum rate of addition depends upon numerous factors. It is best to set the bubble count as low as feasible to begin with, then increase it based upon the performance of the plants. Getting the setting right may take some trial and error. Once you are satisfied with the result, check the pH and KH of the aquarium and refer to the previous post in this series for determining the carbon dioxide concentration of the tank. The optimum is around 12 parts per million.