A 0.5 L mini scuba tank gives you up to 8 minutes of air. After that, it needs filling. You have three options: the manual pump, the 12V/220V mini compressor and transfer from a full-size scuba tank. They do not take the same time, and they do not cost the same over a season.
This guide compares the three ways to refill a mini scuba tank, using our catalogue prices as of 1 October 2026. You will know which method suits your use before you buy.
The three ways to refill, side by side
| Method | Compatible tanks | Stated time | What you need | OXSEA price |
|---|---|---|---|---|
| Manual pump | OX500, OX500Plus (0.5 L) | about 20 min | your arms, no electricity | €159.99 |
| 12V/220V mini compressor | OX500, OX500Plus, OX1000 | about 12 min (0.5 L), about 20 min (1 L) | a 220 V socket or a 12 V battery | €549.99 |
| Transfer from a full-size tank | OX500, OX500Plus, OX1000 | about 1 min for the OX1000 | a filled scuba tank and a DIN or yoke transfer station | transfer station, then filling the scuba tank |
The manual pump: self-sufficient, but physical
The manual pump fills an OX500 or an OX500Plus in about 20 minutes, with no electricity. It does not need a socket. It is the answer for remote spots: camping, a small boat, a cove at the end of a footpath.
The trade-off: those 20 minutes are 20 minutes of pumping to reach 200 bar. The effort grows as the pressure in the tank rises. The pump is not compatible with the 1 L OX1000.
It suits occasional use, with one or two refills per outing and a tight budget.
The 12V/220V mini compressor: comfort, including for 1 L
The 12V mini compressor plugs into 220 V mains power, or into the 12 V battery of a car or boat. It fills a 0.5 L tank in about 12 minutes and an OX1000 in about 20 minutes, with no effort on your part. If you have no access to a full-size tank, it is the only way to refill the OX1000.
Its drawbacks: the price (€549.99) and the need for a power source nearby. On a vehicle battery, where you place it matters: more on that in the section on air quality.
It is the right choice if you refill several times per outing, share the gear with others or own an OX1000.
Transfer from a full-size tank: fast, as long as you have one
A transfer station connects a filled scuba tank to your mini tank, with a DIN or yoke fitting depending on the scuba tank’s valve. Air flows from the big tank into the mini tank until the two pressures are equal. Our OX1000 product page quotes about 1 minute to fill it this way.
A transfer does not create pressure, it shares it. Here is a theoretical calculation, at constant temperature. A 12 L tank at 200 bar filling an empty 0.5 L mini tank settles at around 192 bar. The big tank has lost about 4% of its pressure. The next refill tops out at around 184 bar, then 177, 170 and 163 bar. With a 1 L OX1000, the pressure drops faster: about 185, then 170, then 157 bar.
In practice, a 12 L tank gives about five 0.5 L refills above 160 bar. Beyond that, each mini tank is less full and your time underwater shrinks accordingly. If you already own a scuba tank, or a dive centre can fill one for you, this is the cheapest option to run. The “Refill station Yoke / DIN” video at OXSEA School shows how to connect it.
Running costs over a season
Our assumption: 20 refills of a 0.5 L tank over the season, for example ten outings with two tanks each. For the transfer method, the cost depends on what your local dive centre charges to fill a 12 L tank: divide that price by about five to get the cost of each refill. Every dive centre sets its own prices and conditions.
| Method | Equipment cost | Cost per refill | For 20 refills |
|---|---|---|---|
| Manual pump | €159.99 | nothing, apart from filters | €159.99 + filters |
| 12V/220V mini compressor | €549.99 | power and filters | €549.99 + power and filters |
| Transfer from a 12 L tank | transfer station, and a scuba tank | about a fifth of the price of one tank fill | 4 tank fills + station |
With a scuba tank and a dive centre nearby, transfer is by far the cheapest method to run. Without a full-size tank, the manual pump needs the smallest outlay, and after that only filter maintenance. The mini compressor costs more to buy, but it saves you 20 minutes of pumping at every refill, and it becomes essential for an OX1000 without a full-size tank. If you are starting from scratch, the tank and its refill method also come as a pack, for example the OX500 Pack + Manual Pump (€359.99) or the OX1000 Pack + Mini Compressor (€849.99).
Air quality: filters, moisture and location
You are going to breathe this air, so it is worth taking a few precautions. DAN Europe, an organisation devoted to diver safety, lists among the possible sources of contamination hydrocarbons from compressor lubricants, carbon monoxide from exhaust fumes and impurities in the surrounding air. Carbon monoxide has no smell and no taste: your senses will not warn you.
Moisture is the least well-controlled factor, according to a study published by INRS, the French occupational health and safety institute, covering fifteen years of compressed air analyses at the French Navy laboratory in Toulon. Producing very dry air by compressing ambient air directly is difficult. Too much moisture can promote corrosion in a metal container and, in cold water, cause the regulator to freeze.
- Set up the pump or compressor away from any exhaust (car, boat engine, generator), cigarette smoke and paint fumes.
- Change the filters on the pump and the compressor: they are consumables. The “Changing the filters” videos at OXSEA School show how to do it for each device.
- If the air has an unusual smell or taste (oil, chemicals), stop filling and do not use that tank.
- For a transfer, have your scuba tank filled at a dive centre or filling station that maintains its compressor.
Mistakes to avoid
- Going over 200 bar. That is the working pressure of all three of our tanks: keep an eye on the gauge throughout filling.
- Connecting the manual pump to an OX1000. It is designed for 0.5 L tanks only.
- Expecting 200 bar from a transfer. A scuba tank at 200 bar always gives a little less, and less again with each refill.
- Letting salt dry on the tank. Rinse it in fresh water after every trip at sea and store it away from knocks and heat.
- Relying on smell alone. An abnormal smell should stop you, but carbon monoxide cannot be smelled: your best protection is still to fill away from any exhaust.
A safety reminder
A mini dive tank delivers compressed air, just like a full-size scuba tank, and the basic rule is the same: never hold your breath on the way up. DAN Europe points out that coming up on a held breath from just one metre down can be enough to cause a lung overexpansion injury. Breathe normally, stay shallow and get trained: an introductory session at a dive centre or with an instructor will give you the right reflexes.
Frequently asked questions
How long does it take to refill a mini scuba tank?
About 20 minutes with the manual pump for a 0.5 L tank. About 12 minutes with the mini compressor for 0.5 L, and 20 minutes for the 1 L OX1000. For the OX1000, transfer from a full-size tank is much faster: about 1 minute according to our product page.
Can I refill the OX1000 with the manual pump?
No. The manual pump is for 0.5 L tanks (OX500 and OX500Plus). The OX1000 refills with the mini compressor or by transfer from a full-size scuba tank.
How many refills can I get from a 12 L scuba tank?
In theory, about five refills of a 0.5 L tank above 160 bar, starting from a scuba tank filled to 200 bar. After that, the pressure you get drops with each transfer.
How much does a dive centre charge to fill a scuba tank?
Prices and conditions vary from one dive centre and one country to another, so ask the centre nearest you. Then divide the price of one 12 L fill by about five to get the cost of each 0.5 L refill.
Which method should I start with?
No full-size tank, a 0.5 L tank and occasional use: the manual pump. For the OX1000 or frequent refills: the mini compressor. If you already have a scuba tank and a dive centre nearby: transfer. To choose the tank first, see our comparison of the three models.