Steel V.S. Aluminum Tanks

We often get asked is why we dive with steel tanks and what the benefits are over aluminum. So why would you buy steel?

The pro’s for steel tanks

The buoyancy characteristics of steel cylinders are one of their greatest benefits. Some of you might not know why they tell you to do a buoyancy check with an empty tank. The reason is that an empty aluminum tank is more buoyant than a full tank. This means you need to add extra lead to your weight belt to stay under submerged while diving. A steel tank remains negatively buoyant when empty. This means if you are diving with a steel tank you don’t need to add the extra weight to your BCD which give you better buoyancy control.

Another benefit is higher volume steel tanks are almost the same size or smaller than an lesser volume aluminum tank. Steel is a lot stronger than aluminum, and because of this, the walls of a steel tank can be a lot thinner, giving you more space for air.  A 100cft steel tank is about the same size than an 80cft aluminum tank, but gives you 20cft more air and a longer dive time. For shorter individuals a regular 80cft tank can be too tall, whereas an 80cft steel tank is shorter making it a better fit.

The con’s for steel tanks

The price is the biggest con. Steel tanks can be twice as expensive as aluminum ones. Even second-hand steels keep their value. The other issue is rust on the inside. Aluminum tanks seldom corrode on the inside, but if you drain a steel tank and let moisture get in the tank they will rust. In practice this isn’t a big issue as you should never drain a tank completely. You should minimally leave 500psi in your tanks to keep moisture out.