How do you fill a paintball tank? HPA tanks are filled using a fill station or scuba tank that delivers compressed air at 3,000 or 4,500 PSI. CO2 tanks are filled with liquid carbon dioxide from a bulk supply or exchanged at a sporting goods store. Both tank types require proper equipment, attention to pressure ratings, and a current hydrostatic test date.
| CO2 | HPA | |
|---|---|---|
| Fill method | Bulk liquid CO2 transfer or tank exchange | Fill station (compressor) or scuba tank |
| Fill pressure | ~850 PSI (liquid weight determines fill) | 3,000 or 4,500 PSI (depends on tank rating) |
| Fill time | 1–3 minutes | 30–90 seconds |
| Typical cost per fill | $3–$5 | $3–$5 |
| Where to fill | Paintball fields, sporting goods stores, welding supply shops | Paintball fields, scuba/dive shops |
| DIY at home | Not practical (requires bulk CO2 tank) | Possible with a scuba tank and fill adapter |
| Overfill risk | Tank rupture, burst disc failure | Tank rupture, burst disc failure |
How to Fill an HPA Tank
HPA tanks are the standard for most players. If you are unsure which tank type you have, check the label on the tank body. HPA tanks will be rated at either 3,000 PSI or 4,500 PSI and will say “compressed air” or “nitrogen.” For a full breakdown of the differences, see our CO2 vs HPA guide.
Using a Fill Station
A fill station is the most common way to refill an HPA tank. Paintball fields, pro shops, and some sporting goods stores have fill stations connected to a high-pressure compressor or large storage tanks.
Here is the process:
- Check the tank’s hydro date. Look at the label or stamp on the tank. Every HPA tank must be hydrostatically tested every 3 or 5 years (depending on the tank manufacturer). If the hydro date has expired, no reputable shop will fill it.
- Connect the tank to the fill station. The fill station has a standard ASA (Air Source Adapter) fitting. Thread your tank’s regulator into the fitting by hand, then snug it with a quarter turn. Do not overtighten.
- Open the valve slowly. The fill station operator will open the air valve gradually. Filling too fast generates heat inside the tank, which causes a temporary pressure spike called a “hot fill.” A hot fill reads higher on the gauge than the actual pressure once the tank cools. Slow fills give you a more accurate, complete fill.
- Watch the gauge. Fill to the tank’s rated pressure. A 3,000 PSI tank gets filled to 3,000 PSI. A 4,500 PSI tank gets filled to 4,500 PSI. Never exceed the rating stamped on the tank.
- Disconnect and check. Close the valve, bleed the fill line, and unthread the tank. You should hear no hissing from the regulator or valve.
Most fill stations at paintball fields are self-service. The staff will show you how to use it on your first visit. Some fields include unlimited air refills with your entry fee.
Using a Scuba Tank
A scuba tank and a fill adapter let you refill HPA tanks at home or at the field without needing a compressor. This is a popular option for players who want convenience or play at fields with no fill station.
You will need:
- A scuba tank rated at 3,000 or 4,500 PSI (filled at a dive shop)
- A scuba-to-paintball fill adapter (also called a scuba fill station or remote fill whip)
- A bleed valve on the adapter line
To fill from a scuba tank:
- Connect the fill adapter to the scuba tank’s valve.
- Attach the other end to your paintball tank’s ASA fitting.
- Open the scuba tank valve slowly. Air will transfer from the higher-pressure scuba tank into the lower-pressure paintball tank.
- Watch the gauge on the fill adapter. Stop when you reach the paintball tank’s rated pressure.
- Close the scuba valve, bleed the line, and disconnect.
One scuba tank will fill a paintball tank multiple times before the scuba tank itself needs a refill. A standard 80 cubic foot scuba tank at 3,000 PSI can fill a 48ci paintball tank roughly 15 to 20 times. The number drops as the scuba tank’s pressure decreases with each fill. For help choosing the right tank size, see our best paintball tanks guide.
How to Fill a CO2 Tank
CO2 tanks work differently from HPA tanks. Instead of compressed gas, CO2 tanks hold liquid carbon dioxide. The tank is filled by weight, not by pressure.
Bulk CO2 Fill
Paintball fields and some specialty shops fill CO2 tanks directly from a bulk CO2 supply. The operator places your tank on a scale and fills it until it reaches the correct weight for its size. A 20-ounce tank, for example, gets filled with 20 ounces of liquid CO2.
The process:
- The operator connects your tank to the bulk CO2 supply via a pin valve or on/off adapter.
- The tank is placed on a scale to monitor fill weight.
- Liquid CO2 is transferred until the correct weight is reached.
- The valve is closed and the tank is disconnected.
This takes 1 to 3 minutes. Most paintball fields can do this quickly between games.
CO2 Tank Exchange
Many sporting goods stores, including Dick’s Sporting Goods and some Walmart locations, offer CO2 tank exchanges rather than refills. You hand over your empty tank and receive a pre-filled one. This is often the most convenient option for recreational players. The exchange cost is typically $3 to $5, similar to a bulk fill.
Tank exchanges have one downside: the tank you receive might be older or more worn than the one you turned in. Check the hydro date on any exchanged tank before using it.
Safety Rules for Filling Paintball Tanks
Filling paintball tanks involves high pressure. Cutting corners can cause serious injury.
Never Overfill
Every tank has a maximum rated pressure or fill weight stamped on its body. Exceeding this rating puts dangerous stress on the tank walls. HPA tanks should never be filled past their PSI rating. CO2 tanks should never be filled past their weight rating. Overfilling is the single most common cause of burst disc failures and tank ruptures.
Hydrostatic Testing
All paintball tanks require periodic hydrostatic testing. This test verifies that the tank can safely hold its rated pressure. HPA tanks are tested every 3 to 5 years depending on the manufacturer. CO2 tanks are tested every 5 years. The test date is stamped or printed on the tank. Expired tanks should not be filled or used until retested. A hydro test costs $20 to $35 at most dive shops.
Burst Discs
Every paintball tank has a burst disc, a small safety plug designed to rupture before the tank itself fails. If you hear a loud pop and your tank rapidly vents all its air, the burst disc has blown. This usually means the tank was overfilled, exposed to extreme heat, or has a defective disc. Replacement burst discs cost a few dollars and can be installed at any paintball shop.
Use the Correct Gas
Never fill an HPA tank with CO2. Never fill a CO2 tank with compressed air from an HPA fill station. The tanks, regulators, and pressure systems are not interchangeable. Using the wrong gas can damage equipment and create a serious safety hazard.
Where to Get Paintball Tank Fills
Finding a fill location depends on your tank type and where you live.
Paintball Fields and Pro Shops
This is the easiest option. Almost every paintball field fills both CO2 and HPA tanks. Many include HPA fills with your admission fee. If you are new to the sport, the field staff will walk you through the process. For a breakdown of what a typical day costs, see our guide on how much paintball costs.
Scuba and Dive Shops
Dive shops can fill HPA tanks to 3,000 PSI and sometimes 4,500 PSI. They can also fill scuba tanks that you use as a home fill source. Expect to pay $3 to $7 per fill. Call ahead to confirm they fill paintball tanks, as some shops only service diving equipment.
Sporting Goods Stores
Stores like Dick’s Sporting Goods handle CO2 tank exchanges. They typically do not fill HPA tanks. This is a convenient option if you run CO2 and have a store nearby.
Welding and Industrial Gas Suppliers
Welding supply companies like Airgas sell CO2 and can fill CO2 paintball tanks. This is less common but useful if you cannot find a paintball-specific fill location.
How Much Does a Fill Cost?
Both CO2 and HPA fills typically cost $3 to $5 per tank at a paintball field. Some fields offer unlimited HPA refills as part of the entry fee, which usually runs $15 to $30. Scuba shops may charge $5 to $7 for HPA fills. CO2 exchanges at sporting goods stores run $3 to $5. For players who shoot frequently, investing in your own scuba tank ($150 to $250 used) pays for itself within a season.
How to Know When Your Tank Is Empty
HPA Tanks
HPA tanks have a pressure gauge built into the regulator. When the needle drops to zero or near zero, the tank is empty. You will also notice a significant drop in shot velocity and distance before the tank fully empties. Most markers will start “shooting hot then cold” as the regulator output pressure falls below the marker’s operating threshold.
CO2 Tanks
CO2 tanks do not have a gauge in most setups. The most reliable sign is performance: shots become noticeably weaker, the marker starts short-stroking or failing to cycle, and the tank feels significantly lighter. Some players weigh their CO2 tanks to check remaining capacity. A full 20-ounce tank weighs roughly 20 ounces more than the empty tank weight listed on its label.
If you are building your first setup and trying to decide between tank types, our guides on the best paintball tanks and the best paintball guns for beginners cover everything you need to pick the right combination.