Your scuba regulator is the most important piece of equipment you will own. It should be treated with respect and cared for. This is the one piece of equipment that without you cannot breathe under water. This includes the regulator that you have attached to your bailout bottle. Like all other scuba equipment there is no shortage of options to choose from. This is one piece of kit that I suggest not going for the cheapest, as a well designed and made regulator makes the dive so much more enjoyable. If I ever find myself in the position where I have to use rented regs, I cringe.
Components of a regulator
A regulator consists of three main parts:
Primary second stage
Alternative second stage
The first stage connects directly to your tank either via a Yoke or DIN connection. Depending on where you live one type is usually more popular than the other. For example in Asia, you will struggle to see divers using DIN. A yoke connection sits over the tank valve and is clamped on, whereas a DIN screws directly into the tank valve. I started off with Yoke and Switched to DIN. DIN connections are more stable and therefore, safer. For example, if you are diving in a wreck and you manage to hit the connection hard, there is less of a chance that something might break. The chances are low, although scuba safety is about minimising foreseeable risks. If you do decide to buy DIN, I would suggest that you buy a Yoke converter and keep it in your kit bag, so if you ever are somewhere and they won’t let you unscrew the valve insert or you can find an Allen key you are still good to use your regulator.
The two most common types of first stages are unbalanced or balanced. A balanced first stage regulator will deliver consistent air flow regardless of depth and tank pressure and conversely an unbalanced regulator will become harder to breathe from as depth increases and or tank pressure decreases. For this reason alone I would opt for a balanced setup.
How scuba regulators work
The primary purpose of a regulator is to deliver air at a rate and pressure that you can breathe no matter what depth your are at. The first stage converts the high-pressure air in the tank to an intermediate pressure. From there the gas travels down the hose to your second stage. The second stages job is to then convert this intermediate pressure to ambient pressure. This allows you to breathe freely at whatever depth you may.
A couple of years ago I had to lead a journalist on a dive so that he could do an article on the local diving. It was a bad weekend, massive swell, and all the boats were canceled, although he was on a short time frame and insisted I take him out on a 40-meter wreck. I was uncomfortable as it was, but when I saw him putting his kit together, I asked, where is your alternative air? He replied I don’t need one. I couldn’t believe it, I thought that was the most selfish thing I have heard to date as a diver. Your alternative air source is predominantly for your buddy in times of need. I doubt that this is a common occurrence, although it does illustrate that you should always be your own buddy first and carry redundant air.
As discussed your alternative regulator or octopus, is there if something goes wrong with your primary second stage or your buddies.
The primary and second stage regulators are essentially the same, although usually manufactures use a cheaper model for the alternative and change the colour to yellow.