Join Date: Jan 2013
Location: out wandering around
The pressure doesn't build too high, it starts out that high. Co2 in a bottle runs anywhere from 800psi and up. The hotter the temp the bottle is stored at the higher the pressure inside it will go. It's really not that big of a deal for aquariums that are in a climate controlled environment. I would be careful not to leave a full co2 bottle in your car on a hot day.
Your first step will be to get the co2 down to a workable pressure so you don't blow up other equipment hooked up down line. A co2 regulator does this. Some have gotten away with just a needle valve to control it but you are using one tiny valve to go from 800psi to 1-2 bubble per second. The risk of something not going right is a lot higher and you are lucky to have 130 pages of past experience to glean through in the provided link. Good luck and don't be afraid to ask more ?'s
Also, click the link in my signature for how I built my regulator.