Scuba Octopus

The Scuba Octopus: How To Set Up Your Scuba Gear

Your lifeline underwater is your regulator. Should you run out of oxygen, or it suddenly gets damaged during a dive, you are in serious trouble! That’s why a scuba octopus, or spare regulators, are very crucial for you and your buddy.

A scuba octopus is your backup air source. It must be in place and correctly set up because what is the use of a spare if it won’t work? This guide will help you correctly set up not just your scuba octopus but also the rest of your scuba diving gear.

So what is the scuba octopus?

Parts of a Scuba Octopus:

Scuba Octopus

The scuba octopus gets it’s name from the many tubes and hoses that stem from the first stage and wrap around the diver like the tentacles of an octopus. It’s made up of the following four components:

Diving Regulator

Brings pressurized oxygen from the oxygen tank to your mouth.

Scuba Regulator

Spare Diving Regulator

It is used to share oxygen with a buddy in case of a malfunction or out-of-air situation.

Inflator Hose

It is used to inflate or deflate your BCDs using the air from your oxygen tank.

Diving Console

It helps monitor your air supply while underwater. It also measures how deep you have gone and could even be equipped with a compass.

The scuba octopus’ standard setup is two regulators connected to a hose and with a dive gauge. It’s relatively straightforward since there are only a few things involved. However, you need to do it properly, or it could end up useless.

Now, let us look closely at how to put these things together so that your scuba octopus will function as it should. In this guide, you will learn the following:

How to attach the regulator to the tank

Scuba regulator parts

Diagram for scuba regulator setup

How the scuba regulator functions

Proper maintenance of scuba regulators

Gear assembly guide

Pre-dive equipment check

How to attach the regulator to the tank

When you already have your scuba octopus set prepared, the next thing that you need to do is to connect it to your oxygen tank.

It might seem a bit tricky to do this initially, but the next ones will be a lot easier when you got it right the first time.

Regulator Setup

There are two steps involved in the first stage. Initially, you have to attach the Buoyancy Controlled Device or BCD to the tank. Use the straps which can be found at the back of the BCD.

The next thing you need to do is connect the first stage to your scuba diving oxygen tank’s cylinder valve.

The first stage regulator is the mechanism where pressure reduction happens. It helps regulate the air that comes out of the tank as it passes through the hose.

How to connect the first stage regulator to the oxygen tank:

Now that you have set the first stage, it is time to connect it to the tank.

The first step in doing this is removing the cover of the valve. You need to unscrew the metal knob found on the first stage and then take off the dust cover.

Place the second stage regulator on your BCD’s right side while the gauge is on the left.

Connect the intake valve of the BCD to the scuba octopus’s inflator hose.

Once you finish with the above steps, you need to test if both the regulators are working. Open the air tank by turning the cylinder valve. Work the user controls — breath through both of the regulators to check if they are working correctly. Then, depress the purge buttons. 

You also need to ensure that you attached the intake valve correctly. Press the deflate and inflate button found in your BCD to see if it works.

The above steps are elementary, but it is understandable if you find it challenging on your first try. If you need help, you can ask from the instructors or your fellow scuba divers. Even if just to double-check if you did it right because this part is very crucial to your safety.

Scuba regulator parts

Now, let us backtrack a bit to study the different parts of your scuba regulator.

Full Scuba Octopus

1) First Stage

The first stage body, as stated earlier, houses the mechanism that lowers the air pressure.

It is a cylindrical metal where the air enters. It adjusts the air pressure enough before it gets released to the second stage.

Most divers identify this as the end of the octopus. The four parts are connected: the two regulators, the pressure hose, and the dive gauge.

The first stage has several parts:


Also called a DIN, it is used to connect the scuba tank to the first stage’s body. It often comes with a yoke screw, which is used to secure the regulator to the tank.

Dust cap

The dust cap is what keeps the water from getting into the body of the first stage regulator.

It is a small rubber cap found at the opening of the regulator’s first stage. You will also need the yoke screw to secure its position.

Ports and Port Plugs

You will find many ports and port plugs on the first stage body. These are where you will connect the different hoses that you will need. If not in need, you will use the port plugs to keep them sealed.

You will realize that there are more ports than necessary. It is to allow you to choose the position you want the hoses to be for your convenience.

2) Primary second stage

The second stage is the regulator’s part that goes into your mouth; it comprises the purge valve and the mouthpiece. You will attach this to the first stage using the LP hose.

Its primary function is to reduce intermediate-pressure air from the hose to an ambient pressure that is safe for the diver to breathe in.

Purge button

It is located at the face of the second stage regulator. When you press the purge button, the air is forced into the chamber of the second stage.

Ease of breathing adjustment

Most regulators are equipped with ease of breathing adjustment. Through it, the divers can adjust their breathing resistance using a lever.

The adjustment is very crucial because it hinders the free flow of air. It is a condition where there is a continuous flow of air which the diver cannot control.

Exhaust valve

An exhaust valve’s primary purpose is to channel exhaled bubbles away from the diver’s face to prevent blocking the view.

A clear vision is vital when diving, not just to enjoy but mostly for safety. You can find the exhaust valve just below the mouthpiece.


The mouthpiece is what you use to breathe underwater. You put it in your mouth to access the oxygen coming from your tank.

3) Alternate Second Stage

The alternate second stage is also referred to as an alternate air source or a buddy regulator. It has the exact same function as the primary second stage. An LP regulator hose connects this to the first stage.

As it functions the same way as the primary second stage, the LP hose is where the air is transported from the first stage going to the second stage. It is often longer than the direct hose for easier access by the diver in need.

More often than not, this part is not employed, which is a good thing because it functions as a backup. It is used when out-of-air situations are occurring while underwater, meaning there is an emergency.

When you are diving, and your buddy runs out of air, either due to misuse or malfunction, the alternate air source can be used to share air coming from your tank.

4) Submersible pressure gauge and console

It is essential to monitor how much air you have left in your tank when you are underwater, and that is what the submersible pressure gauge (SPG) does.

The SPG is connected to the first stage using a high-pressure hose. It sends high-pressure air from the oxygen tank directly to the pressure gauge.

Aside from the pressure gauge, the console may include a compass, a dive computer, and a depth gauge.

5) Low-pressure inflator hose

The low-pressure hose feeds intermediate pressure air to the buoyancy compensator (BC) from the regulator’s first stage. It enables the diver to add air to their BC from the tank when necessary by pressing a button. 

A sleeve is used to attach the low-pressure inflator hose to the BC inflation mechanism. Hold the sleeve backward when connecting the hose to the inflator.

The BC inflator is connected to the LP hose using the attachment opening, which comes in various measurements.

Diagram for scuba regulator setup

If you do not have all the parts in front of you, it will be hard to imagine how all the above elements come together. Here is the diagram for the entire scuba regulator setup. Examine it closely to better visualize how it will look once you assemble everything correctly.

Credit: Natalie Gibb –

How the scuba regulator functions

The scuba tanks are very crucial in diving because that is where you get your air while underwater. However, the compressed air it holds is a very high pressure; it is fatal to directly breathe from it.

The regulator, or the scuba octopus’ whole setup, functions to reduce the pressure into ambient pressure safe enough for the divers to breathe.

The regulator uses the different hoses and valves to convert the high-pressure air and sends it to the mouthpiece for the diver’s consumption.

The scuba octopus reduces the pressure from the tank via two stages. The first stage involves the reduction of pressure from the tank into intermediate pressure. Then the intermediate pressure is converted to ambient pressure in the second stage.

Let’s dig deeper into the specifics of these two stages below.

Regulator first stage

In the regulator first stage, high pressure from the tank is reduced to intermediate pressure using different parts. After the reduction, the hose’s air will already be safe for the divers.

It is made of two chambers with a valve that separates them. The valve is open when the regulator is not pressurized. The high-pressure air travels from the first chamber going to the second chamber when connected to a tank.

Once the second chamber reaches intermediate pressure, the valve splitting the two will then close. It helps keep the high pressure from the tank to go fill the second chamber.

A typical open water style regulator has four different hoses connected to its first stage. Each of the hoses has various functions.

One hose is connected to a submersible pressure gauge directly from the tank. The others are either channeling the gathered intermediate pressure into the regulator’s second stage of the BC inflator.

Regulator second stage

The regulator second stage further reduces the intermediate pressure into ambient pressure that is safe for the diver to breathe.

Ambient pressure matches the pressure of the surrounding water, which is needed for safe underwater breathing.

The reduced pressurized water travels through valves and hoses and is connected to a mouthpiece to give the diver access to the air.

The second stage regulator is made of the primary and alternate second stage. These two are almost the same in composition and function. It is just that the latter is a backup air source for other divers who might experience emergencies during a dive.

Proper maintenance of scuba regulators

Rarely does a scuba octopus set up tear quickly. It’s a good investment because it can last for years. However, for that to happen, you have to ensure that it’s well-maintained and serviced regularly.

Bringing your dive gear to a service center once a year would be good enough to keep your stuff in good shape and for tuning up.

With enough training, you can do the maintenance on your own; otherwise, you need help. It may seem simple, but it goes through a lot of assembling and disassembling to ensure that everything is properly inspected and cleaned. Sometimes, replacement of parts may even be necessary, and only an expert eye can determine that.

During the tune-up, every detail and every part must be scrutinized. Check for any salt damages, lubricate or replace O-rings and threads if necessary, ensure the gauges are correctly working, and replace valves, hoses, and connections if needed.

If you tend to go around in different places to do your scuba diving, it is best to get your octopus regulator from popular brands. It’s not for the fad but because their replacement parts are usually available even in remote areas, so should the need arise, you will not have trouble.

It cannot be emphasized enough how vital the scuba diving octopus is. Thus, you must take care of it, especially if your dives are frequent. Give it professional service to guarantee that all is working fine. It is your lifeline underwater, so don’t even think twice!

If you rarely go scuba diving, the best way to take care of your regulator is to have it serviced before storing it. You need to make sure that there are no salt damages that could get worse in time. It is quite an investment, take good care of it.

Gear assembly guide

Now that we have exhausted all that you need to do to set up and maintain your scuba octopus let us proceed to the rest of your gear. The regulator may be the most important among them, but if you fail in ensuring the correctness of the rest of your equipment, you could be putting your safety at risk.

Scuba octopus assemply

Setting up your equipment is part of the introductory course you need to take when getting certified to scuba dive. Every step is crucial. You need to flawlessly execute them before you go. If you need a refresher on how it is done, just continue reading below.

Fasten the BCD to your tank

First, you need to wet the straps of the BC. Then, ensuring that the BC is aligned to the tank valve, slide the straps over the tank. Pull the straps tight to secure the BC straps. Check if it’s tightly secured by lifting the tank using the BC shoulder straps.

Turning the air on

Before you begin, make sure that the gauges are facing down and away from you. With your other hand, slowly open the valve all the way and then turn back half a turn. See if the pressure is correct by looking at the pressure gauge. 

Attaching first stage regulator to the tank valve

Uncover the tank valve, unscrew the knob found on the first stage, and then take off the dust cover. Attach both the first stage and second stage to the tank. The octopus must be located on the right while the console is on the left of the BCD. Finally, connect the inflator hose on your BC’s intake valve.

Prepare the mask

Thoroughly rinse the mask. Use a defogger to clear the visuals. On the left side of the dive mask, secure the snorkel. It is best to wear the scuba mask on your neck rather than on your head in between usages.

Fasten the buoyancy weights

Ensure that you fasten your weight belt in such a way that it can quickly be released by your right hand. To do this, put the belt on the floor, with the buckle on your left. Hold each end of the weight belt and wrap it around your waist. Buckle it up securely.

Pre-dive equipment check

If you are a regular scuba diver, you probably mastered all you need to do before starting a dive. However, it is excellent for novices to keep a checklist of what needs to be done pre-dive. Below is a list that you may use for quick reference before splurging in. Check them out and be guided accordingly.

Scuba Gear Check

Exposure suits

Any tears, rips, or damages?

Are the zippers working fine? (Lubricate if necessary)

Gauges and regulators

Are the O-rings and hoses in perfect shape?

Gauges working correctly? Are they secured in place?

Inlet screens are free from debris and discoloration?

Are the parts of the second stage regulators functioning?

Masks, fins, and snorkels

Are the straps in perfect condition? Do they hold, OK? (replace if needed)

Is there any damage to the mask skirt?

Are the snorkel’s bite tabs still in perfect shape?

Weight system

Can you determine neutral buoyancy?

The weights are correct?

Are the stitches on the belt and harnesses still holding firm?

Are the releases secured and can be operated smoothly?

Buoyancy compensator

Can the releases, D-rings, and clips be employed with ease?

Are the inflators functioning smoothly? Are all connections secured?

Is the bladder in good condition?

Can you operate the relief valve well? Is it secured?


Are all the other accessories in good condition?

Are there visible wears and tears?

Ask these questions before your dive. If there are things that are not right, ensure that you address them before diving. Even the most superficial issues, like a tear on your suit, may lead to underwater emergencies. Do not take your chances to maximize the enjoyment of this activity.

Before you go

You have everything that you need, from your scuba octopus to all the other gear you will use to go on your dive. You are well-informed about how to set up, what to check, how to maintain, and so on.

All of this information guarantees that you are well on your way to having that enjoyable and, most of all, secure dive!

Just one last thing. Always remember to keep refreshing everything that you know whenever you go scuba diving. Do not rely on memory because they tend to get rusty. Do this mostly if you have not gone diving for quite some time.

Nevertheless, experienced divers must also take precautions. Just go through each topic, or just pick the ones you think you need to be reminded of. Safety must be your top priority.

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