To maintain your aluminum dive tank, always rinse it thoroughly with fresh water after each use, especially the valve area, to remove salt and debris; store it in a cool, dry place away from direct sunlight; and have it professionally visually inspected annually with a hydrostatic test every 5 years to check for internal corrosion and ensure its structural integrity remains safe for diving.

Rinse After Every Dive

They attack the alloy (commonly 6061-T6 aluminum) and the protective oxide layer, leading to corrosion that can permanently condemn your cylinder. A proper rinse isn't just a quick splash; it's a deliberate 2-3 minute process that protects your investment.

Here’s the exact breakdown of what you need to do, every single time you surface:

The cost of neglect is high: a professional visual inspection ($30-$50) might reveal corrosion so severe that the only fix is an $800+ hydrotest or, worse, the tank fails and is condemned entirely.

• Never use high-pressure spray directly on the valve diaphragm or dust cover.

• Avoid using soap or detergents, as residues can contaminate your regulator and air supply.

• A dedicated tank rinse tool that attaches to your hose can make flushing the valve interior much easier and more effective.

This isn't just about cleaning; it's a non-negotiable 5-minute insurance policy that directly extends the typical 20+ year service life of a well-maintained aluminum tank. 

Store in a Cool, Dry Place

An ideal storage spot maintains a relative humidity below 50% and a stable temperature between 50°F and 80°F (10°C - 27°C). Storing a tank in a humid garage or a hot car trunk can accelerate corrosion rates by a factor of 4x or more compared to a controlled environment.

Here’s the science behind it: As the ambient temperature fluctuates throughout a 24-hour cycle, the air inside the tank expands and contracts, literally "breathing" in the damp, humid air from your storage room.This is why you should always store your tank with about 100-200 PSI of air pressure inside. Never store your tank for extended periods (over 24 hours) completely empty (0 PSI). 

• Avoid direct sunlight at all costs. The UV radiation and intense heat can degrade the tank's epoxy liner over time, and sitting in direct sun can cause the internal pressure to spike by over 100 PSI, putting unnecessary stress on the cylinder.

• Concrete is porous and constantly wicks moisture, which will transfer to the tank's metal surface, often leading to a ~5 mm diameter ring of concentrated corrosion on the bottom edge after just a few months.

• Use a vertical tank rack or store it horizontally on a rubberized shelf. If you must use a boot, ensure the tank is completely dry before putting it on, and periodically remove the boot to check for moisture trapped underneath.

A tank stored correctly in a cool, dry basement can easily achieve its full 20-year service life and pass every hydro test. One left in a damp, hot shed might show significant internal corrosion at its 5-year visual inspection, cutting its usable life in half and turning a $300 asset into a worthless piece of metal.

Annual Professional Visual Inspection

A certified inspector uses a specialized borescope—a flexible optical scope typically 0.5 to 1.0 mm in diameter—to see every square millimeter of the tank's interior, a process that takes a trained professional 15 to 20 minutes per tank. They are looking for the microscopic beginnings of issues you'd never spot, and the cost for this critical service averages between $30and$50, which is a trivial investment compared to the risk it mitigates.

A single pit deeper than ~0.005 inches (0.127 mm) in certain areas can be a reason for further scrutiny. They also meticulously examine the threads where the valve screws in for any signs of wear, galling, or cross-threading that could compromise the seal—a failure here at 3000 PSI is no joke.A dent with a depth exceeding ~0.015 inches (0.38 mm) or one located near a seam can concentrate stress and become a failure point over time.

Finding a tiny issue this year might mean a simple advisory to monitor it, potentially saving you from a catastrophic "condemned" result at the next 5-year hydrostatic test. A tank that fails hydro is immediately taken out of service and must be rendered unusable, a total loss of your $300-$500 investment. The visual inspection is your early warning system, a high-resolution snapshot of your tank's health that allows for proactive maintenance, ensuring the cylinder remains in service for its full 20+ year lifespan.

Perform Hydrostatic Testing Every 5 Years

The process is brutal and precise: your tank is filled with water, placed inside a safety chamber, and then pressurized to 167% of its working pressure. For a standard 3000 PSI aluminum tank, that means it's subjected to a staggering 5010 PSI for a predetermined hold period, typically 30 seconds or more. If the expansion exceeds a very strict limit—often a ~5% maximum permanent expansion rate of the total volumetric expansion—the tank fails immediately and is condemned.

The entire process, including valve rebuild and new visual inspection, usually costs between $50and$80, a small price for a 5-year license to use your equipment with confidence.

The 5-year interval is calculated to catch degradation long before it ever approaches a critical probability of failure.It resets the clock, guaranteeing that your gear isn't just clean on the inside, but is fundamentally sound all the way through its ~0.5-inch thick aluminum walls, ensuring it remains a safe asset for its entire 20+ year design life.

Keep Your Tank Secure

A single fall from just 3 feet onto a hard surface can generate a ~5000 G impact force, enough to create a dent deeper than the 0.015 inch (0.38 mm) fail limit or, worse, cause a hidden hairline fracture in the neck or shoulder. Your tank's $300 value can go to zero in under 1 second. The goal is 100% stability, 100% of the time, whether in transit, in storage, or on a boat deck.

A direct impact to the valve can easily cause $150+ in damage, bending the stem, cracking the housing, or shearing the O-ring seat, leading to a sudden and total loss of air. The physics are simple: a standard 80 cubic foot aluminum tank weighs roughly 31.5 pounds when empty and over 35 pounds when full.

• During Transport: A simple $15 nylon strap with a quick-release buckle is the minimum requirement. Never let tanks roll around freely in your trunk; a sudden 15 MPH stop can send a tank flying with over 200 pounds of force into the back of your seats.

• On the Boat:If no rack is available, lay it completely horizontal on a non-slip surface and secure it with a 3-inch wide webbing strap. A vertical tank is a falling hazard. On a boat rocking at 10 degrees of roll every 5 seconds, an unsecured tank will walk itself to the edge and fall in under 60 seconds.

• In Storage: A vertical stand with a ~20-inch diameter stable base is ideal. The worst thing you can do is lean it against a wall at a ~70-degree angle where a minor bump or vibration from a 40 dB sound source can knock it over.

• Valve Protection: The $10 plastic valve cover is not optional. This prevents grit, sand, and impact damage to the critical first-stage threads and the valve orifice, which has a machining tolerance of less than 0.001 inches.

A secure tank maintains its physical integrity, passes its annual visuals and 5-year hydro tests on schedule, and achieves its maximum 20-year service life.