The next piece of essential equipment we will require for a pressurized CO2 setup is the regulator.
A regulator takes the tank pressure of the CO2 tank (normally at ~850 PSI or more, depending on the ambient temperature) and reduces it to a lower pressure.
We normally look for a regulator with two gauges.
This means there are two pressure dials. The first pressure dial (high pressure dial) will indicate the pressure in the CO2 tank (i.e. the amount of CO2 that is remaining in the tank). The second pressure dial (low pressure dial, also known as the delivery pressure), will be the pressure that the regulator is bringing the CO2 down to. This is usually set anywhere from 5-20 PSI, depending on the size of your tank, and the desired bubble rate.
Sometimes, we also here the term dual stage
used. Note that dual stage
and dual gauge
the same. These terms are sometimes used interchangeably, but this is incorrect.
Dual stage refers to an additional body within the regulator that allows the pressure to be dropped in two stages, hence the name. Here are two figures that show the differences between the two:
Single stage regulator:
Dual stage regulator:
As the finer details are beyond the scope of this primer, more information regarding the differences can be found over at the Barr Report, where Left C and I are quite active as well.
There has been a lot of debate over whether a single stage regulator or a dual stage regulator is best. There are often stories about people encountering "end of tank dump" (when the CO2 tank pressure begins to drop, there is sometimes a phenomenon in which all the CO2 will suddenly rush out of the tank, ending up in your aquarium and subsequently gassing all your fish to death) when using a single stage regulator. Some people will blame this on the regulator, while others will point out that it was a combination of a single stage regulator and a poor needle valve. Yet others will point out that despite having a single stage regulator and a sub-standard needle valve, they have yet to encounter "end of tank dump".
In the end, whether you purchase a single or dual stage regulator is up to you; dual stage regulators are the "premium" regulators, and will work reliably for our purposes. Single stage regulators will also work well for our purposes, and are often cheaper than dual stage regulators (more on this later).
Some good brands that I recommend:
Single stage regulators:
Dual stage regulators:
Finally, when purchasing your CO2 regulator, regardless whether it is a single or a dual stage regulator, be sure that you have the correct fitting (CGA320), or else it will not fit the CO2 tank. Sometimes, you may be able to find cheap regulators on eBay (more on this below) that do not have the correct fitting (most commonly found are those with a CGA580 fitting, used for nitrogen ). If this is the case, you can take off the fitting and replace with the appropriate CGA320 fitting.