Click on the pictures below to expand each image and read through the directions. 

To begin the set up process of the Co2 system, you will need a filled cylinder. What size tank you buy depends on how often you want to have to fill it.  Shown is a standard 5lb tank. This should last roughly 4-5 months on a nano tank of 6-9 gallons depending on how much Co2 you use in a given day. Once you have a filled tank, you are ready to start assembling the other parts of the system. Begin with attaching the regulator to the threading of the tank. It is not recommended that you use teflon tape on the threads as it increases the risk of getting pieces of the tape inside the regulator, which can ruin it. However, in our experience, we like the security that the teflon provides  against leaking,  so if you want to use it we recommend only putting it on the rear 50% of the threads thus keeping the lead threading free of the teflon tape, ensuring that no tape gets into the regulator. Before attaching the regulator to the threading double check that the 0-ring is in place within the inner core of the threading. Most regulators require only hand-tightening to attach them securely to the tank, however if you feel it needs more, there is nothing wrong with a light quarter turn of an appropriate sized wrench but you do not want to apply much torque  and you do not need to make it as tight as possible to get a secure fit. Please read the instructions that come with your regulator so that you know what else needs to be done before turning on your system. In some cases you will be asked to loosen the working pressure knob on your regulator before attaching to the system. You will also want to make sure that your speed control valve,  also called the flow adjustment valve, is closed or off. This is important. 

It is now nessessary to take your Co2 safe pressure tubing and attach it to the regulator. 

Unscrew the Co2 line connector nut from the regulator as shown. Slip the Co2 tubing through the nut. Then place the tubing over the tubing nipple  on the regulator and tighten the nut to secure the tubing. 

Next, place the other end of the pressurized tubing on to  the bottom of the Co2 safe check valve, you will know which end is the bottom by the arrow that is printed on it pointing to the top.  A Co2 check valve is necessary to prevent water from the tank  or the bubble counter from getting into your regulator  when the Co2 system turns off..

You will now need to attach the Co2 safe flexible tubing to the top of the check valve. Using pressurized tubing throughout is fine but you will find it difficult to attach it the  glassware like bubble counters or diffusers. Pressurized tubing also is not near as flexible and will not take the drop over the glass and into your tank as nicely as flexible Co2 line. You could also use flexible Co2 tubing throughout, however flexible tubing can expand in areas of greater pressure and has a much better chance of popping off. The use of both types of tubing is highly recommended.

If you are using an in-line bubble counter, this would be installed next an inch or two above the check valve. 

Fill the bubble counter with water. As  the gas passes through you will see a bubble form in the water allowing you to count the bubbles going into your aquarium.

Pllace the bubble counter at an upright position on the outside of your aquarium.  The purpose of the bubble counter is to give you an  idea of the amount of Co2 going into your tank. The rate of measure is known as "bubbles per second". This rate will be adjusted using the speed control valve found on your regulator or speed controller.

Finally attach the  other end of the flexible Co2 tubing to your Co2  diffuser. 

Your are now finished installing the hardware portion  of your system.  The next step is to plug the solenoid into a grounded outlet or electrical timer. Using a timer will give you an important advantage as you will want to run the system on the same schedule as your  lighting. Some hobbyists find there is a  slight advantage to using two timers so that the Co2 can come on roughly an hour before the lights and shut off one hour before the lights go off. Now you can open the valve on your Co2 tank slowly to release pressure to the regulator. You will now want to adjust the working pressure of your regulator. Usually the recommended working pressure is about 30-35 psi but you will want to check as to what your regulator instructions recommends. Finally, you can now adjust the speed control or flow adjustment valve to reach the desired rate of C02 (bubbles per second). Please ask your local planted aquarium experts on what rate they recommend. This has to do with the size of the tank, species of plants you are using, and how many plants are involved. Either way, as your plant density and growth increases, it may be necessary to turn up the bubble rate. You will need to give the system 5 -10 minutes to push Co2 through the lines before you can expect to achieve a consistent bubble flow rate. Even then, it sometimes takes up to 30 minutes to get an accurate reading of your flow rate to determine if you need to make any adjustments to the flow adjustment valve.