- What sort of diving do you or will you be doing?
- How important is performance to you?
- Do you intend to travel regularly?
Most importantly be as honest as you can with yourself about what sort of diving you plan on doing. I know it can be difficult to foresee what will spark your interests in the future given the huge number of different avenues you can go down but a little forward thinking here can save you spending more than you need to or avoid shelling out for an upgrade at a later date.
We have also filmed product videos for the vast majority of the regulators we sell, don't forget to check them out for more information.
Cold or warm? Deciding whether you'll be braving cold water (by cold I mean sub 10ºC) is really the biggest filtering option. If you intend diving somewhere in the UK all year round then there is a very good argument for looking for a cold water rated regulator with an environmentally sealed first stage. The advantage of a sealed first stage is that it's an entirely watertight, helping to prevent ice forming on important internal parts and also prevent contamination. A strange statement you might think as surely a first stage shouldn't let in water...well yes and no. For those that might not know how a first stage works here is a quick overview. Every first stage needs access to the surrounding ambient pressure to balance out the forces inside the housing, making them balanced. When the first stage is pressurised but idle the intermediate pressure (the air that is supplied to the second stage) matches the opposing forces from the ambient pressure. When a diver breathes the intermediate pressure becomes lower and the ambient pressure helps to push open the valve. Air rushes in from the cylinder until the divers stops inhaling, allowing the intermediate pressure to equalise with the water and push the valve shut. Now, an environmental seal prevents that water from getting inside and helping to equalise that pressure so manufacturers have to use a secondary means to transmitting the load into the first stage. It's pretty easy to spot a sealed first stage, a diaphragm design uses a dry chamber, second diaphragm and transfer pin whilst piston first stages need to be packed with silicone grease and capped over with a rubber ring to keep the grease in place.
An environmentally sealed piston first stage with capping ring in the centre
An environmentally sealed diaphragm first stage with dry chamber and second diaphragm.
The answer also helps steer a diver towards certain regulators based upon how many low and high pressure ports a first stage has. A diver who dives primarily in cold water is very likely to use a dry suit which means four low pressure ports are required. A holiday diver that only entertains nice tropic temperature waters isn't interested in dry suits so won't need that extra low pressure port. Also consider whether you'll want to upgrade to a wireless air integrated dive computer. Most divers still feel more comfortable using an analogue pressure gauge as well as a transmitter so a second high pressure port is required to accommodate the transmitter.
Unbalanced or Balanced? The next big question for you is about performance at depth. Most regulators now are balanced or even over-balanced. Balancing basically involves adding extra components to the mechanism to compensate for the additional water pressure as you dive, maintaining or even increasing the regulator performance at depth. This can be implemented at just the first stage or at both the first and second stages for ultimate performance. Unbalanced regulators will ever so slightly degrade in performance the deeper you dive and also as the cylinder pressure drops (only really noticeably below 50 bar when you should be nearing the end of your dive anyway!). They are, of course, a lot simpler and therefore cheaper but their simplicity makes them incredibly reliable and easy to maintain. There is also the hybrid option of balanced first stage and unbalanced second stage. As the first stage does most of the work anyway, there is a good argument to save yourself a little money and opt for a lower specification second stage. This is a popular option, giving the depth compensating performance of a balanced first stage with the high reliability and still very respectable performance of an unbalanced second stage.
Apeks XTX 40 DST Regulator
Scubapro MK25 G260 Regulator
The weight of a regulator is obviously critical if you intend to travel a lot and are limited by airline restrictions. A cold water rated, full metal heavy duty regulator with all the bells and whistles will weigh twice as much as a lightweight compact regulator that is made using composite materials.
These few simple questions can really help narrow down your choices and cut out the regulators that aren't suitable for you.