Lung Tank vs. BLU3: Which Mini Dive System Is Right for You?

Q: Are mini scuba tanks meant for full dives?

No. Mini tanks, roughly 3 cu ft, are backup air supplies. Real world breathing time is typically about 3 to 4 minutes at about 10 ft (3 m), and can be shorter with depth, exertion, or stress. A 6 cu ft mini tank may provide roughly 6 to 8 minutes in similar conditions.

Q: Can I add a backup to BLU3?

Yes. Spare Air is available as an add on backup for Nomad and Nomad Mini for divers who want an emergency option in addition to their primary surface supplied system.

Honest comparison of refillable mini scuba tanks (backup air) vs. tankless surface supplied systems (primary air).

If you’re exploring portable diving systems, you’ve likely seen both Lung Tank and BLU3. They may look similar as both are marketed as compact, travel friendly ways to breathe underwater, but they’re designed for very different purposes. This guide compares them side by side, explains the true role of mini scuba tanks (backup, not primary), and helps you choose the right solution for yacht maintenance, treasure and fossil hunting, or pool work. BLU3 continues the Brownie’s Third Lung heritage of building floating dive compressors since 1969.

What’s the Main Difference?

Feature	Lung Tank (Mini Tank)	BLU3 (Nomad & Nomad Mini)
Intended Role	Backup air supply (emergency / ascent aid)	Primary air source for shallow diving surface supplied
Realistic Use Time*	About 3 to 4 minutes for roughly 3 cu ft (T-500) at about 10 ft (3 m) depth; breathing rate and exertion change this	Nomad 45 to 60 minutes per battery Nomad Mini 40 to 45 minutes per battery
Extended Use Options	About 6 to 8 minutes for roughly 6 cu ft (T-1000) at about 10 ft (3 m) under similar conditions, about double the air of the 3 cu ft cylinder	Nomad Mini: up to about 120 minutes with the DiveBoost Kit
System Type	Small high pressure cylinder plus regulator, often paired with a full face mask	Battery powered floating compressor, tankless, surface supplied
Depth Guidance	Mini tank guidance: do not exceed ~10 ft (3 m); sub-mask limits may be shallower	Nomad 9 m (30 ft) Nomad Mini 4.5 m (15 ft)
Refill / Recharge	Refill cylinders at a compressor or dive shop, the promoted hand pump is unrealistic	Recharge batteries from an outlet or onboard power, or swap with a spare battery
Training Path	Often sold without structured training	Includes BLU3 Online Dive Training Course, available free without a purchase, certification is always recommended
Best For	Emergency backup for certified divers	Recreational shallow diving, yacht and boat upkeep, treasure and fossil hunting, pool inspections and repairs
Typical Price	About $500 to $900, bundle dependent	$1,649 to $2,199 (Nomad Mini / Nomad)
Warranty	Varies by seller	1 to 2 years standard, optional extended coverage

*Realistic mini tank time depends on depth, breathing rate, exertion, and cylinder volume. The “about 3 to 4 minutes” note refers to roughly 3 cu ft cylinders around 10 ft (3 m) under typical conditions.

Important notes on depth and origin: According to the Lung Tank manufacturer guidance, using the Lung T 500 or T 1000 at depths greater than 3 m / 10 ft is prohibited, and the Sub Mask accessory is limited to about 2 m / 6.5 ft. These limits reinforce that mini tanks are intended for very shallow, short duration use. Also note that Lung Tank products are manufactured in China while the company is based in Australia, and local dive shop repair or warranty support may be limited.

1. Real World Dive Time and the True Purpose of Mini Scuba Tanks

There is a common misconception that mini scuba tanks can keep you underwater for 10 to 20 minutes. In practice, that is not how these small cylinders are intended to be used. For roughly 3 cu ft mini tanks, actual breathing time is often about 3 to 4 minutes at around 10 ft (3 m), and can be shorter with increased depth or exertion. A 6 cu ft mini tank has about double the air volume, so time may be roughly 6 to 8 minutes in similar conditions. Divers of all experience levels treat mini tanks as backup air supplies, tools to make a controlled ascent or handle a brief contingency, not as a primary air source for exploration.

Standard practice with conventional scuba is to reserve about 10 to 15 percent of the cylinder rather than breathing to empty. This helps protect regulator health and avoids pulling salt water into the tank when pressure reaches zero. That reality makes it even less realistic to use a mini tank as a recreational primary air source. The exception is an emergency backup such as Spare Air, where breathing the cylinder completely in an emergency ascent is appropriate.

The category leader for backup air is Spare Air, a long established, USA made product trusted by divers for decades. Spare Air is purpose built for emergencies and ascent support, with straightforward, truthful marketing about what mini tanks can, and cannot, do.

BLU3 and Spare Air are sister companies under the same parent family. We share engineering knowledge and a commitment to responsible, transparent education. We even offer Spare Air as an add on for BLU3 Nomad and Nomad Mini, so divers who want a backup to their surface supplied primary can carry a proven emergency option.

Bottom line: If you need a backup air supply, choose a product designed and marketed for that role, see Spare Air. If you want a primary air source for longer shallow dives, choose BLU3’s tankless systems.

2. Training, Certification, and Responsibility

Neither mini scuba tanks nor BLU3 systems replace formal scuba certification. BLU3 includes an Online Dive Training Course to teach essentials such as buoyancy, ascent control, and emergency procedures, supporting more responsible shallow water diving. Access to the BLU3 Online Dive Training Course is free, no purchase required. Certification and hands on instruction are always recommended.

Reminder: All diving involves inherent risks. Proper training, conservative dive planning, and medical fitness are required. Never treat a mini tank as a primary air source for exploration, understand the limits of your equipment.

3. Use Cases: Which Is Better for You?

Backup Air Supply, Emergency / Ascent: Choose Spare Air. It is the proven mini tank for certified divers who want an emergency option, truthfully marketed and manufactured in the USA.
Pool Service and Leak Detection: Choose BLU3 Nomad Mini. Continuous surface supplied air for 40 to 45 minutes per battery, up to 120 minutes with the DiveBoost Kit, supports inspections and quick repairs without refilling cylinders.
Yacht Owners and Boaters: Choose BLU3 Nomad. For quick checks, such as untangling a line from the prop, a mini tank may not provide enough air to complete the task safely. Nomad gives you a continuous air supply to finish the job without rushing. Compact onboard solution for hull cleaning and gear recovery, batteries recharge from your vessel’s power system.
Treasure and Fossil Hunting: BLU3 systems let you spend real time underwater in shallow areas where finds are common, without the refill logistics of small cylinders.
Short Recreational Dives and Photos: A mini tank can provide a brief novelty experience, for meaningful shallow exploration, BLU3’s tankless systems are the right primary tool.

4. Cost of Ownership

Mini tanks appear cheaper up front, but ongoing refills add cost, time, and logistics. BLU3 systems recharge from standard outlets or onboard power, no air fills, and offer optional extended warranty coverage. Over time, many users find BLU3 more practical and cost effective for repeated shallow water work.

5. Safety and Limitations

Mini tanks are backup tools, not replacements for primary air systems or formal training.
The full face mask commonly sold with mini tanks is buoyant, often requires a weight belt to stay submerged, can increase breathing effort, and is a struggle for many first time divers.
BLU3 systems float at the surface and use patented Smart Reg™ demand delivery technology to supply air efficiently during shallow dives.
Always dive with a buddy, monitor time and depth conservatively, and follow local regulations.

6. Which One Should You Choose?

Choose Spare Air if you want a backup air supply from a long proven, USA made brand that markets mini tanks for what they truly are, emergency tools. Visit Spare Air.

Choose BLU3 if you want a primary air source for shallow diving that delivers continuous air without refilling tanks, ideal for pool pros, yacht owners, and recreational users who value responsible training and ongoing support. See Nomad Mini | See Nomad

Prefer a traditional scuba experience with more capacity, yet compact gear? Consider the Easy Dive by Submersible Systems combined with the Snorkelator for a practical way to carry a reasonable amount of air and switch between snorkel and regulator. Planning for multiple divers or longer sessions from a boat? Explore Brownie’s Third Lung multi diver tankless systems built on decades of engineering for reliable surface supplied air.

Frequently Asked Questions

Are mini scuba tanks meant for full dives?
No. Mini tanks, roughly 3 cu ft, are backup air supplies. Real world breathing time is typically about 3 to 4 minutes at about 10 ft (3 m) under normal effort, and can be shorter with depth, exertion, or stress. A 6 cu ft mini tank may provide roughly 6 to 8 minutes in similar conditions.

Is BLU3 “safer” than a mini tank?
Safety depends on training, planning, and responsible use. BLU3 provides an Online Dive Training Course and a primary surface supplied air system for shallow diving. Access to the BLU3 Online Dive Training Course is free, no purchase required. Mini tanks are appropriate as a backup, not as a primary.

Can I add a backup to BLU3?
Yes. Spare Air is available as an add on backup for Nomad and Nomad Mini for divers who want an emergency option in addition to their primary surface supplied system.

Do I need certification?
Certification is always recommended for any compressed air diving. Training and supervision help ensure responsible, informed use of any system.

Compare Systems in Action

Real diving with Nomad:

See how divers use BLU3 systems for extended time underwater.

Every BLU3 System Includes:

Access to the BLU3 Online Dive Training Course, available to everyone without purchase
U.S. based support and warranty service
Optional extended coverage

Final Takeaway

Mini scuba tanks are backup air, best used for emergencies and controlled ascents. For that role, we recommend Spare Air, a USA made, truthfully marketed product with a decades long track record. If you want to actually spend time underwater for shallow tasks and exploration, choose a primary surface supplied system like BLU3 Nomad or Nomad Mini.

Shop Nomad Mini Shop Nomad Shop Spare Air