Voodoo Gas, Blend it Baby!

Voodoo Gas, Nitrox, or to give it the correct name, Enriched Air Nitrox (EANx) is still a mystery to some people. Why use it, why pay for the course to learn how to use it, and what are the benefits? I found out the answers to these questions many years ago when I did my PADI EANx Course. Back then it wasn’t that common, hence the nickname ‘Voodoo Gas’.

Nitrox Tank

For the uninitiated, EANx is used by divers in order to have longer dives at certain depths due to the fact that the percentage of oxygen is increased. This means that the percentage of Nitrogen is decreased, nitrogen being the limiting factor in depths and times of dives. Normal air is 21% oxygen and 79% nitrogen, whereas the two most common blends of EANx are 32% or 36% oxygen leaving only 68% and 64% nitrogen respectively.

One of my biggest questions, however, remained unanswered – ‘How do we get Nitrox into our tanks?’ – I had a rough idea but it wasn’t until I recently undertook my PADI TecRec Gas Blending Course that this was fully answered!

For the first time in a while the instructor became the student as I was handed my Gas Blending Manual and told to complete Knowledge Reviews 1,2 and 3….now don’t get me wrong but I am used to being the person asking students to give up their evenings to study, now I am being asked! Oh well, for the greater good…

The next morning I met up with Wilco, who was to be my instructor for the next couple of days, and we walked through the reviews, adding ‘meat to the bones’ where we needed so I had a full understanding of how EANx is blended and the possible hazards of the differing procedures and how we avoid them.

Next it was onto the practical side of things and actually learning to fill a cylinder with nitrox rather than normal air. Knees knocking, I followed Wilco to the compressor room and started to learn all about all the workings of the complressor and how to blend different mixtures of gases correctly – but only after a stark warning from Wilco – ‘When filling nitrox, please don’t blow up the compressor room!’ – now I am not usually a nervous individual but that got the sweat trickling down my neck, or was that the 38 degree heat?

Gary Blending Nitrox

So we worked step by step through everything from attaching the tanks to the filling whips (the hoses used to put the Nitrox into the cylinder), to startup steps for the compressor, to how we add the oxygen to the normal air to achieve the desired percentage blend and finally to the full shutdown upon the fill of all the cylinders needed.

Ten cylinders later I felt comfortable in blending Nitrox, as long as I followed Wilco’s expertly written step-by-step guide! I went on to complete the rest of the Knowledge Reviews and take the final exam…scored an 88%…not too shabby!

I have been regularly blending and filling our Nitrox cylinders since my course and am getting more comfortable each and every time. I may even be able to ditch the step-by-step guide sometime soon!

For anyone who hasn’t got their PADI Nitrox Certification yet I highly advise doing it, maybe in conjunction with your PADI Advanced Open Water Course and that way, you too can experience ‘Voodoo Gas’ on your next dives!

PADI Self Reliant Diver Course

The PADI Self Reliant Diver course – so what made me decide to do this? After all, I am an instructor and dive centre manager, with not an insignificant number of dives under my belt; what else could I learn about e.g. my air consumption that I didn’t already know? As it turned out… quite a lot!

It was during a dive at Twins, one of Koh Tao’s most popular scuba diving sites, with a DM friend of mine and her Open Water certified boyfriend that the idea first came to me. My friend was, quite rightly, being the perfect buddy to her inexperienced boyfriend, and I thought “What if something happened to me right now?’ and it occurred to me that, whilst I was certainly not in any imminent danger, if I did suddenly have an equipment failure, who would be there to help me? Then I cast my mind back to when I was teaching full-time and again it struck me that as a dive professional there isn’t really anyone to look after you, should things go wrong. At that point I decided that I really did want to do this less well-known PADI course. Having done the first of the PADI Tec courses, Tec 40, a few years back, I knew from that training that you have to be prepared to end any dive and get back to the surface, no matter what the situation or the conditions, on your own. So doing the PADI Self Reliant Diver course made sense.

As soon as I got back onto the boat, I spoke to Wilco, our Tec and Self Reliant Diver instructor, and told him I wanted to do the course. “Why?” was his immediate answer; to which I carefully and knowingly responded “So I can dive alone”. Having worked with Wilco for the best part of 7 years, I knew precisely how he would react and what his next word would be: ”Wrong!” was his immediate response as I smirked cheekily at his predictability! And what Wilco said was completely correct; the premise of the Self Reliant Diver course is not so that you can simply dive alone; it is to provide you with the skills and knowledge to dive independently, whether that be leading a group of students, diving with other dive pros (let’s face it, most of us are too busy doing our own thing underwater!), or if the situation arises, diving solo, as in the case of underwater videographers and photographers. The course also makes you far more prepared as a buddy.

Wilco, Charlotte and Elaine
Wilco, Charlotte and Elaine ready for their dive!

I managed to persuade Elaine, co-owner of Master Divers, to do the course with me – which that meant double trouble for Wilco! Whilst there is no manual for the course, we still had a Knowledge Review to complete. Calculating our Surface Air Consumption (SAC) rate was the first job. Until we did the first dive, we would have to estimate it which we did at around 12L; we then had to determine, individually, how long we were going to dive for, at what depths and how long at each depth, using several formulae (don’t worry if Maths is not your strong point – they are straightforward); we then had to work out, using our estimated SAC rate, how much air we would use during the dives. What we found after the SAC rate skills (swimming as fast as we could for 1 minute at a depth of 10m and recording our start and finish pressure) was that our SAC rates were identical at 5.5L. Even Wilco was surprised at how low they were!

There are 3 dives for the course, and for the first 2 dives, you are with your instructor, as there are a number of skills that they have to assess during the dives. Having planned the dive ahead of time, we were each allocated a dive to lead. First off was the Self Buddy Check, which is exactly the same as a normal buddy check, but you are doing on yourself. As well as the required skills for the dive, we had to record our depth and pressure at 10 minute intervals and then our time and depth at specific pressures, regardless of what we were doing at the time, which may have been whilst doing a 2 minute no mask swim at 10m, switching from our back gas to our redundant air source and back, swapping from our regular masks to our spare masks, recording times and pressures in order to calculate a normal SAC rate at various depths, plus several more skills which seem a bit of a blur now; and all the time continuing to stick to the original dive plan that we had individually calculated, and making sure that we got back to the planned exit point. Those two dives that first afternoon were pretty full on, but great fun!

A few days later, we were back on the boat for the final dive of the course and our first solo fun dive! A double dive to Chumphon Pinnacle, which is located about 13km from Koh Tao,  and Elaine and I were both very excited! For the final dive of the course, we again had to plan our dives, this time using our actual SAC rates, to determine how long our air supply would last at much deeper depths. After a few adjustments – we were both somewhat over enthusiastic about how long our air would last according to the formula – we both had our individual plans! The Self Buddy Check were done, and as we agreed, we descended  down the buoy line together; once at the bottom of the buoy line I chose one direction and Elaine the opposite.

Elaine Self Reliant Diving
Elaine Self Reliant Diving

And then I was alone! Looking at my slate to re-assure myself as to the tasks I had to complete during the dive, I set off to explore on my own. All I can say is it was awesome! As I gazed out across Chumphon Pinnacle, going exactly where I wanted to go, without having to wait for my buddy or catch up with anyone, I felt completely at ease. Now I understood what all my underwater videography/photography mates were talking about! At the end of the dive, having followed my plan, the final skills to complete the course were the SMB deployment and then the 3 minute safety stop whilst breathing from the redundant air source. I had already bought myself an 85L “Spare Air”, and although I had had a short go with it on a previous fun dive, it was good to know that I didn’t run out of air on the safety stop!!

Elaine and I came up from our dives within a few minutes of each other, and were both very excited to tell each other about our first solo dives! I don’t think either of us listened to the other because we were both so busy talking at each other!  An hour later, we were ready to jump in again for our first post-course solo dives – no skills – just diving. I spent the best part of 30 minutes ambling around Chumphon Pinnacle, without seeing even the bubbles of any other divers. I have done a fair amount of dives, peering in amazement at wonderful and weird critters, riding along heart-stopping currents and hanging with mantas, dolphins and mola molas, but this was definitely up there in my top 10 dives.

So what did I learn – planning is paramount, regardless of how experienced you are as a diver; knowing your strengths, and your weaknesses, to better prepare yourself in the event of a mishap or emergency; and appreciating that no matter how long you have been diving or how experienced you are, there is always something new to learn!

A big thank you to my instructor, Wilco, and to my “non-buddy”, Elaine!! Let’s do it again!!!


My first dive.

This is the story of Jasmin our Eco Queens first diving experience.

I never intended on learning to dive, I was travelling around Thailand for 5 weeks in the summer holidays during my second year of university and had planned to go to Koh Tao but had already decided against diving as it wasn’t in my budget.

Jasmin Diving


Whilst on the boat from mainland Thailand to Koh Tao some of the people I met on the journey down from Bangkok persuaded me to do it with them, we got off the boat, had a couple of hours to sleep and it was straight into the theory! Wow, I thought, this is a lot to take in plus I’m SO tired, I’m not so sure I want to do this. After the first theory session was over I collapsed on my bed to continue with the homework given to me for that evening. I knew the next day was going to be a long one with more theory in the morning and our first water session in the afternoon, so it was an early night for me. The next morning theory went by easily, I had finally got my head around it, the next step was the confined session, this I was really nervous about, all the equipment seemed very daunting and heavy, I really wasn’t sure that diving was for me. We hopped in the pool and put the equipment on in the shallows of the pool. Our instructor the briefly explained the upcoming skills and told us to put our masks on our faces and regulator in our mouths and that we were going to all kneel down on the bottom and get comfortable with breathing through the regulator. The first minute of breathing underwater was the most adrenaline fuelled 60 seconds of my life, I did not enjoy it at first, I stood up out of the water and began to cry, the Dive Master Trainee (DMT) who was assisting our course calmed me down and asked if I wanted to give it another go, I’m not one to give up at the first hurdle so agreed to try again, this time the DMT calmy took me down and allowed me to take my time to get accustomed to the new sensation, after a couple of minutes I signalled that I was OK and it was straight into the skills, given the fact that the sensation of breathing under water for the first time had caused me such distress, everyone myself included expected me to have issues with the skills but I breezed through it and by the end of the session I was having the time of my life, I couldn’t wait for the open water dives the next day!

The following day we got on the boat which droves us to the dive site, we set up our gear, had a dive briefing, got into our equipment, buddy checked and were off! We descended nice and slowly down the buoyline and all I could think was ‘OH MY GOODNESS THIS IS INCREDIBLE!’ Within the first 5 minutes of the dive I was hooked, by the end of the Open Water Course I knew I wanted to be a professional diver. For me diving was a form of relaxation, even in the first dives when I was getting used to the equipment and trying not to swim with my arms  and trying to control my buoyancy I found it so soothing.

After my trip to Thailand I decided to finish university and save up some money and come back to Koh Tao and train to be a Dive Master, and that is what I did, I was lucky enough to be offered a job at Master Divers combining two of my greatest passions; diving and marine conservation and I haven’t looked back since!

Surveying Buoylines

What to consider before booking your open water course.

The first thing you need to consider is your health and the medical form.

Certain medical conditions may prevent you from diving, such as asthma and heart conditions. There are many more that could mean its unsafe for you to dive too so as you have not dived before please take a moment to have a look at the medical statement.  In Thailand you only need a doctors clearance to dive if you have one of the listed conditions otherwise you can simply complete the form upon arrival. If you have one of the listed conditions, please be honest. It wont necessarily mean that you can’t dive but it does mean you need to see a doctor first. It is always better to see your own GP before leaving versus leaving it to chance here in Thailand. Your own doctor knows you better whereas here a local doctor is more likely to say no if in doubt. In some instances your GP may refer you to or ask you to consult with a doctor qualified in dive medicine so make sure you don’t leave this until the last minute.

You do need to have a reasonable fitness level to dive. You don’t need to be super fit but you do need to look after yourself. Diving does place physical demands on you and you will need an average level of stamina and fitness to complete the course.


You do also need to be able to swim. Participants need to complete a 200m swim or 300m snorkel but there is no time limit in which to complete this.  Participants also need to be able to float for 10 mins too.  If this is not in your level of comfort please do consult your dive centre for their recommendation as to how you can enjoy the ocean if your abilities are less than this.

If you have a fear of fish, the ocean, open water or water in general its worth considering if committing to the full open water course is the best place for you to start. Most dive centres offer snorkelling or a try diving experience of some kind. These will get you into the water with no pressure and give you the chance to see what you think first.


Make sure you have enough time to complete your diving. Remember you need to leave 24 hours in between your last dive and flying.





How to be a good student.

This isn’t about being teachers pet or bringing your instructor coffee/chocolate/beer (after diving). Not that that wouldn’t be appreciated mind you! Being a good student will ensure that you get the most out of your course and your instructor too.


Firstly carefully read and clearly complete what can seem like the endless forms that are required. Please be truthful on the medical form and also regarding the swimming requirements if you are taking an open water course.

Be on time, it’s polite, and it ensures that no one’s time is wasted and nothing gets rushed. Island time doesn’t apply to scuba diving; we need the boat and the classes to run on time!

Listen to your scuba instructor at all times; don’t sit on your phone checking out Facebook. What they are telling you effects your safety and could save your life!

Do your homework! You have paid good money for this course so get the most out of it; otherwise you are wasting your money!

Stay with your buddy, its very exciting underwater but swimming off and leaving your buddy puts them at risk as well you. This will also cause your instructor to come after you which will be disruptive to the entire group.

Take care of your payment in a timely manner.

Take care of the rental equipment and treat it as if were your own.

Be conscious and aware of the others in your group, their needs and feeling too.

Make sure you keep an open dialogue with your instructor otherwise they cant help you if you are cold, feel unwell or don’t understand something.

Follow these simple tips to ensure your course is fun for everyone in it!

Leave us a comment below and tell us what makes a good scuba instructor and you might see this featured on our blog in the future.



Top 5 things to remember on the first dive of your open water course.

Apart from all your gear, your buddy and your pre-dive safety check there are a number of things to remember. The following are the most common things new divers forget in the nervous excitement of their first open water dive.

Ready to Go !
Ready to Go !

1)      Relax.

Remain calm, remember to breath out as well as deflating to go down. Over-excitement and nervousness will increase your breathing rate making it harder for you to control your buoyancy. It will also mean you use your air faster too. Remember that shallow breathing means that you will not get the best air exchange through your regulator which can lead you to increase your breathing rate further and so the problem gets worse. Slow, steady and relaxed breathing is what you are aiming for.

2)        Maintain proper diving position.

You need to be perfectly horizontal in the water which is not a common position for landlubbers and can feel a little awkward at first. It’s common for new divers to orientate themselves slightly upright.  As your fins will propel you in the direction that your shoulders are pointing then this can have you heading for the surface. As you will likely have air in your BCD this will expand with the reducing pressure and speed your ascent.

Like this....
Like this….

3)      Don’t use your arms.

Diving is not swimming but it’s difficult to drop that mental in water association at first. Using your arms only wastes energy and therefore air in your tank. Flapping can make it difficult for you to attain neutral buoyancy too, cause you to hit your buddy or the reef.  If you are flapping your arms, ask yourself why…what are you trying to do? If it’s because you feel like you are sinking then instead breathe in and/or add a little air to your BCD. If it’s because you are trying to come down then stop all movement and exhale. If that doesn’t work come upright and deflate a little air from your BCD.


4)      You need to be upright to deflate and let air out of your jacket.

Not only do you need to be upright but you need to hold the low pressure inflator hose high above your head and even slightly leaning back to let the air out. Remember air wants to travel upwards and it cant pass around a bent hose.  When you come upright to do this remember to stop kicking your legs otherwise you will kick yourself up to the surface.


5)      Fin from the hip.

If you have never used fins before they can feel awkward and ungainly. Stretch your legs out behind you and kick from the hip not the knee. You do not want to have a bicycle motion. This is very inefficient and will waste air and energy. Long leg strokes and think about it more like you were kicking a football than riding a bike.


Phew !  Awesome job …3 more dives to go !

The Value of the Buddy Check

Whether divers are on a course or fun diving, as dive professionals we spend a lot of time teaching and reminding divers about the buddy check. Each training agency offers a different view on how the steps are structured and there are so many mnemonics to help you remember it that it verges on the ridiculous.

This post is not about that debate but rather reviewing the importance of a pre-dive safety check. In the end, it doesn’t matter how you remember it, as long as you have a structured process and you use it.


Buddy Check
Buddy Check


So lets look at a scenario shall we? Suppose we have a couple kitting up on a small boat. You can walk around but it’s simply kit and divers. The couple have been seated opposite each other and they gear up separately. The dive is a drift dive which requires a negative entry and they backward roll off opposite sides of the boat and plan to meet each other underwater.

Without a buddy check they can not confirm that each diver’s air is on or that they have remembered their weight belts. If one diver has no air but went straight down and the other diver has no weight then they can’t help their buddy either. A simple run through each others air, buoyancy and weight systems would have circumvented this scary situation.


Ready to go !
Ready to go !


I find all too often that after being certified, divers no longer think a safety check is required or can be too shy to do it in front of other divers who are not checking their buddy before getting in.

Ask yourself this, how many times do you forget where your keys, phone, wallet, etc. are?   So then it’s conceivable that you can make a mistake – we are all human after all.

The check doesn’t take long and no matter what your experience level, it is every divers responsibility to do it. The more it’s seen being done, the more it will be done and eliminate the panic,stress or emergency situation caused by a problem that can easily be avoided.

When should you refresh your scuba skills?

Each dive centre will have its different policies as to when they require divers to make a refresher course.

Where I worked in the Maldives, a full refresher was not required unless you had not dived for 2 years or more. However they insisted that every diver make a check dive off the house reef. This included performing mask clearing, reg recovery and clearing and an out of air drill before enjoying the calm still water close to the island. This dive was necessary as divers needed to have a chance to get into the water, blow the cobwebs off and check their weight before heading to a dive site which would very likely have strong current. It also gave the dive staff an opportunity to assess the divers and be able to advise them accordingly.

Be comfortable and confident.
Be comfortable and confident.

At Master Divers, we recommend that if you haven’t dived for 6 months or more then you should make a refresher. However, there is some leniency here and we do take into account the number of logged dives and the frequency of logged dives too. We also have the option of a private guide taking you to a shallow calm dive site first.

Our policy is different from that Maldivian dive centre as the centers diving process is different. At Master Divers we don’t have a house reef and shallow lagoon we can take you out on. We strongly believe that refreshing your skills is essential for not just your own safety and enjoyment, but also for divers that you are diving with and our team.

Can you remember what this bit does and how to put it together?
Can you remember what this bit does and how to put it together?

Can you imagine for a second, a diver joining your group for the days diving who had not dived in a few years. They might not remember much. They might struggle putting their gear together, not know how much weight they need, have forgotten the crucial safety checks etc.. and this is all before getting in the water! If this diver was to be your buddy it turns what should be a relaxing holiday dive into a worry.  What if they forget to check their air or can’t remember how to clear their mask? You can see why we take this seriously for every diver.

Regardless of a dive centres policy it’s crucial to your safety and that of your buddy to keep your skills up to date. When did you last practice an out of air drill? How comfortable are you to remove your mask underwater? Could you take your gear off in the case of entanglement? Can you remember how to check for proper weighting?  Most divers only practice these techniques when they learn them on their open water course, a refresher gives you the opportunity to repeat these drills which will make you a more competent and confident diver.

So please take the request to make a refresher with good grace. Look at it as a great opportunity to improve your technique and grow as a diver. Understand that we not only have your safety and enjoyment in mind but everyone else’s too which should say something about the dive centre itself!

A refresher only costs 1500B and can very easily be fitted into your first diving day.

Check out PADI Scuba Review or SSI Scuba Skills update for more info here.

Free Diving Level 1 – Day 3

Last day of Level 1 Freediving which was a shame.



We started with breathing and relaxing and while I managed some improvement, being ‘at work’ is not necessarily the best place for me to relax. Wilco did really really well and managed over 3mins.  I feel that I do have the skills to keep practicing my breath holding and I know in order to improve, I need to do this  – so watch this space ….



For our last day we headed out to slightly deeper water moored close to the Sattakut wreck and Hin Pee Wee. When we got there, visibility was awesome and fish were swirling around the line. At the bottom there was a small pinnacle just off to the side and an extremely curious Jack/ Trevallies. We also saw a sea snake coming up for air.


Once again we warmed up by performing some free immersion dives; pulling yourself head first down the line. I was really looking forward to this and the feeling I got, particularly on the first dive, was the same…an indescribable sense of peace and calm. After free immersion we moved onto constant weight, which is using the duck dive to start the dives propulsion down. This is followed by using your fins to go further in a fluid streamlined dive.



The line was set at 20m, I managed 17m, and its interesting to note that yesterday 16m was ‘easy’ with free immersion but 17m with fins was my max today. It shows how much oxygen you actually burn finning and how much more relaxed I was with the free immersion.  The day before, when practicing the free immersion I felt I could have gone further and stayed down for longer. Yet l did notice that my dives were shorter when we went fun diving with fins afterwards.


Kanthin - relaxing
Kanthin – relaxing


Today we also practiced some emergency procedures. We had to swim back up to the surface from 10m using only our arms in a scenario simulating lost fins. We also had to surface from 10m without our mask – simulating a lost mask. The final emergency scenario was to surface someone from 1om who has blacked out and perform a simulated in water rescue including in water ventilation.  After this, you can imagine we needed a little rest, so back to the long-tail and off to Japanese Gardens to meet up with the big boat.


We went off in our buddy teams to explore Japanese Gardens and for me, it was so much better than the day before. The site was quieter, I had some longer dives and did actually experience the sense of calm which I experienced on the free immersion dives. I’m very keen to get out with my camera…stay tuned. I would also love the chance to get back in and video the disciplines to make it easier to explain and hopefully share some of the magic we experienced.




It is fair to say that we have all really enjoyed the course and wish we could continue but both Wilco and I have work commitments and TG has to get on with his Instructor Development Course as he is soon to bcome a PADI Open Water Scuba Instructor. Although Wilco and I go on holiday soon, we will definitely do more freediving and Level 2 when we return.


Free Diving Level 1 – Day 2

Today was nothing short of awesome….


We started off running over our study guides and then progressed to breathing and relaxation exercises.  I didn’t do as well as yesterday, I simply wasn’t as relaxed as things were running around in my head. I felt sure though that once we left this would change.

We took the long-tail out to the channel in between Koh Nangyuan and Koh Tao just out from Japanese Gardens in around 16/17m of water.  First, we were practicing the discipline called ‘Free Immersion’. This involves slowly pulling yourself down a weighted line without using your fins to kick. This is a competition discipline in itself and the record for the currently stands at 121m. Clearly were weren’t attempting anywhere near that depth.

TG Hanging Around !
TG Hanging Around !

For us its an ideal next step as we get to practice our breathing and relaxation techniques and head first equalizing using the line for reference.  This is where the day got very interesting and I have no words to describe the feeling on my first dive, awesome just doesn’t cover it.

Within another 2 dives we were all easily diving to 16m.

Just Awesome!
Just Awesome!

Next we practiced our duck dives and had one practice of a constant weight dive. This is similar to free immersion; it is a head first dive using the line for reference yet this time using our fins for propulsion.

Wilco and friends
Wilco and friends

We then headed around to meet the dive boat at Twins and got to go fun diving around the pinnacle. Luckily we managed to meet up with our photographer who took the pictures that you see on the blog !

More tomorrow, cant wait! Our target is 20 meters but I’m enjoying being underwater in this manner…it  is simply awesome regardless.