Most players just starting out do not want to spend much to try out the sport. Newcomers often buy the least expensive tank: the CO2 tank. Most paintball starter kits include CO2 as the air source because tanks are so cheap and readily available. CO2 tanks are lightweight, vary in sizes and can be shipped through the mail, as long as they're empty. Paintball gun CO2 tank sizes range from 3.5 oz to 20 oz with the larger able to deliver around 1500 shots depending on the type of gun used. In general, the smaller the CO2 tank, the fewer shots it will deliver. Small, disposable 12g CO2 cartridges are also available available and come already filled. These are often used in air rifles and paintball pistols.
Competitive tournament players often use expensive, high-tech, ultra-fast paintball marks for the most consistent performance. Only high pressure air tanks can guarantee such reliability when used in conjunction with precision tournament style guns. Such markers are designed to be used only with HPA tanks as the cheaper CO2 will ruin these expensive guns. High pressure air tanks deliver a more consistent performance, as they do not freeze up during rapid-fire play. CO2 is stored in a tank as a liquid; as it's released into the paintball gun, it changes to a gas. This phase change causes the temperature to drop suddenly; when this happens too quickly (as in constant rapid firing), there's not enough time for the tank to warm up again and it starts to freeze. Once the tank gets too cold, the paintball gun begins to shoot sporadically and inconsistently; some balls shoot normally, some drop to the ground and some shoot 10 feet. When this happens, your tank will often appear to have frost on it. At this point the only thing you can do is wait for the tank to warm up again. While this only takes a few minutes, it's still very inconvenient … especially in the middle of battle!
Conversely, high pressure air tanks deliver a consistent air temperature and pressure during their use, regardless of how often the trigger is dropped. As the temperature does not fluctuate, this is much easier on the internal parts of the paintball gun as well. Your marker will shoot better and last longer when using an hpa tank. The only drawback is the cost; high pressure air tanks generally cost between $ 50- $ 200, as compared to spending barely $ 30 for the largest CO2 tank available. HPA tanks also come in your choice of either a carbon fiber or an aluminum tank. The aluminum HPA tank is the least expensive and tenders to resemble a CO2 tank with its square bottom. The most expensive tanks are carbon fiber tanks that not only have round bottoms but also feature an extra layer of carbon fiber. The extra layer greatly improves the longevity of the tanks and helps them stand up to rough treatment.
Finding refills is another consideration in choosing which type of tank to use. Although CO2 tanks are less expensive, sometimes they can be more difficult to refill. Since Wal-Mart no longer provides the refill service it used to, players almost have to live near a paintball field to refill their tanks. Fortunately other sources exist, such as Dick's Sporting Goods and some local gun shops that also sell paintball guns. As a last resort, players can check with the local hospital as to where it gets its air and O2 tank refills. HPA tanks can be refilled from any commercial compressor and is often more readily available.
In most cases, cost seems to be the only deterrent to buying a high pressure air tank, since their performance and durability are so much better than CO2. Even though it can be priced up to five times as much as CO2 tanks, players who upgrade to HPA are always very impressed with how much better their gun performances. Buying a used paintball air tank is not recommended, as they could have damaged and potentially unsafe to use. Also, when buying a new tank, check the expiration date and the current safety rating to ensure that the tank is still safe to use. For the most reliable and safe equipment, always purchase new paintball gear from a reputable dealer.