Coral reefs offer up an avalanche of colors for every visitor. But underwater breathing for a human requires the use of scuba equipment to enjoy that undersea rainbow.

Too much water and you drown you know…

Scuba is an acronym for Self Contained Underwater Breathing Apparatus. A complete scuba setup (for breathing underwater) includes two essential pieces of gear:

The regulator assembly.

The scuba tank.

To fully enjoy the aquatic realm you need some other tools beyond those mentioned above. But the regulator assembly and tank are all that’s required to actually breathe while you’re underwater.

I suppose you could breathe through a hose that runs to the surface. There are units designed to supply air from above. That pretty much restricts your movement while you’re at depth though.

Few recreational divers use surface supplied air for their diving adventures.

The regulator assembly has three parts:

The first stage.

The second stage.

A length of hose.

The first stage of the regulator assembly mounts to the scuba tank. Its job is to adjust the high pressure of the air (or other breathing gas) in the tank downward to around 150 pounds per square inch (psi).

The air then flows to the second stage through a short length of hose that connects the two stages.

Divers hold the second stage in their mouths. A diver breathes in, and out, through this stage. The second stage regulates the 150-psi air to a pressure equal to the atmospheric pressure that surrounds the diver (also called ambient pressure).

Breathing air at higher than ambient pressure is hard, and makes the diver work for every breath. Together, the two stages provide air at a pressure low enough for easy breathing, allowing for a more pleasant diving experience.

When you descend into the depths you’ll normally carry a scuba tank.

Tanks are made of steel or aluminum. The most common tank used by recreational divers today is the aluminum tank. When full, the pressure in this tank is about 3000-psi.

Imagine trying to suck on that when you don’t have a regulating device to slice the pressure down to ambient air like you normally breathe.

Gas in the tank is either normal breathing air (what you breathe every day on the surface) or a mixture of nitrogen and oxygen. Recreational divers mostly breathe from tanks filled with normal air.

How long does the air in the tank last? How long do you get to study all those wonderful colors on the reef?

That depends on a number of variables. Your breathing technique has a big affect on how fast you use air. Other factors include your level of exertion, your diving experience, and how comfortable you are while you’re underwater breathing.