A mini scuba tank lets you breathe for a few minutes underwater without a BCD or a full-size tank: cleaning a hull, clearing a propeller, checking a mooring, exploring a shallow seabed. On a product page, the models look very much alike. In use, the differences come from details people rarely check before buying, such as how you refill the tank or whether you can still find a spare seal years later.
The right model depends on what you plan to do underwater and how you will be able to fill it. If the idea is new to you, start by browsing our mini scuba tank range.
Capacity and air time: put the minutes in context
OXSEA offers two capacities: 0.5 litres (up to 8 minutes) and 1 litre (about 15 minutes). All the tanks are made of 6061 aluminium, with a working pressure of 200 bar.
These times are ballpark figures. Your consumption rises with depth: the regulator delivers air at the pressure of the surrounding water, so each breath draws more from the tank. It also rises with effort: scrubbing a hull against the current takes far more breath than floating over a seagrass bed.
Choose the capacity for the longest task you have in mind, and come up well before the gauge gets near zero. A mooring check can often be done with 0.5 litres. A job lasting several minutes under the hull calls for 1 litre.
In your mouth or on your back
A tank you hold in your mouth is ready in seconds, and it is the most compact format. The OX500 weighs less than 1 kg underwater and has a silicone mouthpiece.
Wearing the tank on your back takes a harness and an external regulator. The tank no longer weighs on your jaw or follows every movement of your head, which makes a real difference once the session gets longer or you need to work. It is the only option on the OX1000. The OX500Plus does both: in your mouth for a quick dip, on your back for a longer session.
How you refill it: often the deciding factor
Many buyers look at this last, yet it shapes how you will use the tank. Before choosing a model, ask yourself how you will fill the tank, and where: at the dock, on the boat, at the dive centre, on holiday with no power socket.
| Refill method | 0.5 L tanks (OX500, OX500Plus) | 1 L tank (OX1000) | Good to know |
|---|---|---|---|
| Manual pump (€159.99) | About 20 min | Not compatible | No electricity needed. Takes physical effort. |
| 12V mini compressor (€549.99) | About 12 min | About 20 min | Runs off a 12 V battery (boat, vehicle) or 220 V mains power. |
| DIN or yoke transfer station | Compatible | About 1 min | You need a filled scuba tank to hand. |
Without electricity, the manual pump is still the most self-sufficient option, for 0.5 litre tanks only. On a boat, the 12V mini compressor connected to the battery is more convenient. In that case, place its air intake away from the engine: DAN Europe, an organisation devoted to diver safety, recommends keeping a compressor’s air intake clear of exhaust fumes, because the air it draws in ends up in the tank. If you have access to a filled scuba tank, the transfer station fills the OX1000 in about 1 minute.
Always work out the full cost, tank plus refill. An OX500 with its manual pump comes to €359.99 as a pack. An OX1000, which needs a compressor or a scuba tank, comes to €849.99 with the mini compressor.
The regulator and the pressure gauge
The regulator brings the pressure of the stored air down to a pressure you can breathe. Properly adjusted, it delivers air smoothly from the very start of each breath. Check that the airflow can be adjusted and that a manual or a video explains how to do it. A serious product page also lists the materials used for the fittings and seals.
The pressure gauge matters just as much. Without it, you cannot know what is left in the tank, so you cannot decide when to come up. It is built into the OX500. The OX500Plus comes with an external gauge.
Spare parts, after-sales service and tutorials
A mini dive tank has wear parts: seals, membrane, safety disc, filters for the pump or compressor. The day a seal wears out, you need to be able to replace it and know how. Before buying, make sure these parts are easy to find and that clear instructions are available in English. Look for an after-sales service you can actually reach, with an identifiable address.
Our OXSEA School groups video tutorials by product: assembling the tank, adjusting the airflow, replacing the safety disc or the regulator seal, changing the filters, leak detection test. Our after-sales service can be reached by email, at the address on our contact page.
The traps of very cheap offers
You can find much cheaper mini scuba tanks online. Some do the job, others cause trouble from the very first refill. Be wary if you spot any of these signs:
- An air time claim with no mention of depth or effort. A flattering round number tells you nothing.
- Neither the working pressure nor the tank material appears on the product page.
- No pressure gauge, or a dial too small to read underwater.
- Vague refill details: a pump described as “compatible” with nothing more, no adapter for a scuba tank, no filter on the air circuit.
- A badly translated manual, no videos, no spare parts on offer.
- A seller with no address or identifiable customer service. If a leak appears, you may never get an answer.
With a tank filled to 200 bar, you should know who made it and who stands behind it.
How the three OXSEA models compare
| Criterion | OX500 | OX500Plus | OX1000 |
|---|---|---|---|
| Price | €199.99 | €289.99 | €299.99 |
| Capacity | 0.5 L | 0.5 L | 1 L |
| Air time | Up to 8 min | Up to 8 min | About 15 min |
| How it is worn | In your mouth | In your mouth or on your back | On your back |
| Manual pump | Yes, about 20 min | Yes, about 20 min | Not compatible |
| Example pack | With pump: €359.99 | With pump: €449.99 | With mini compressor: €849.99 |
The OX500 suits a first purchase and short dips. With the manual pump, you can refill it anywhere, even without electricity.
The OX500Plus has the same capacity, can also be worn on your back (with harness and external regulator) and comes with an external gauge. It is the logical choice if some of your sessions last longer and you want to take the strain off your jaw.
The OX1000 doubles the capacity, for jobs that take time. It is worn on your back and refills with the mini compressor or from a full-size scuba tank. The manual pump is not suitable for it.
To see the three models side by side, criterion by criterion, read our OX500, OX500Plus and OX1000 mini scuba tank comparison.
Safety: the basic rules before your first dive
A mini scuba tank has you breathing compressed air, just like standard scuba gear. The basic rules of diving apply, even two metres down.
Never hold your breath on the way up. The air in your lungs expands as the pressure drops. According to DAN (Divers Alert Network), coming up on a held breath after breathing from a tank, from just 4 feet down (about 1.2 metres), can be enough to injure the lungs. Changes in volume are greatest near the surface. Come up calmly, breathing normally all the way.
Stay shallow and always keep some air in reserve. A mini scuba tank is made for short dives near the surface.
Get trained. Diving with a tank is something you learn: go to a dive centre with qualified instructors. Never dive alone, check with a doctor that you have no contraindication, and mark your position in the water with a buoy and a flag.
Frequently asked questions
What is the best mini scuba tank for beginners?
For short dives near the surface, a 0.5 litre tank with a pressure gauge and a planned way to refill it covers most needs. At OXSEA, that is the OX500. For long jobs under the hull, look at the 1 litre version instead.
Can I refill a mini scuba tank without a compressor?
Yes, for the 0.5 litre models: the manual pump fills an OX500 or an OX500Plus in about 20 minutes, without electricity. A transfer station also lets you fill them from a full-size scuba tank. The OX1000 needs the mini compressor or a scuba tank.
How much air time can I expect from a 0.5 litre mini scuba tank?
Up to 8 minutes in good conditions. The time drops if you go deeper or work hard. Watch the gauge and come up with air in reserve.
Can I go spearfishing with a mini scuba tank?
Check the local rules first. In France, for example, recreational spearfishing with scuba equipment, that is with a tank, is banned. The rules differ from one country to another. We recommend keeping your mini scuba tank for boat maintenance and observation.
Do I need training to use a mini scuba tank?
It is recommended. For any diving with a tank, we advise training at a dive centre with qualified instructors. You will learn the right reflexes, starting with breathing out on the way up. The OXSEA School tutorials explain the equipment, but they do not replace an instructor.