You cannot smell, taste or see carbon monoxide, and underwater it becomes even more dangerous. At depth the partial pressure rises, so every ppm of CO in your breathing gas weighs more heavily than it does at the surface. The tricky part is that the breathing gas in your cylinder can contain carbon monoxide without you noticing a thing, and in the worst case that leads to carbon monoxide poisoning.
Analysing your own breathing gas before a dive is standard procedure. By analysing it yourself you know exactly which mix you are diving, and you avoid accidents. You check the oxygen and helium percentage, but carbon monoxide stayed out of the picture until now. The new Divesoft Echo changes that. It is the first trimix-analyser from Divesoft that measures carbon monoxide alongside oxygen (O₂) and helium, combining all three readings in one compact device that you simply take along to your filling station, the waterside or the boat.
What is the Divesoft Echo?
The Echo is Divesoft's newest breathing gas analyser for nitrox and trimix blends. It measures how much oxygen and helium are in your breathing gas, and now adds a separate carbon monoxide reading. The helium measurement works acoustically, based on the speed of sound in the gas. That sensor does not wear out and does not need replacing under normal use. It is the same trusted sensor you already know from the Divesoft Solo and the He/O2.
The device is round and compact, with a built-in TFT-HR display that shows the readings and the device status. It charges over USB-C and comes in a sturdy EVA case that protects your analyser in transit. It connects over Bluetooth to the free Divesoft app. That makes it a practical tool for technical divers, gas blenders and dive centres to check their blends before a dive.
The big new feature: measuring carbon monoxide
The carbon monoxide reading is the Echo's most important addition, and a real safety gain at the same time.
Outdoor air normally holds around 0 to 10 ppm of carbon monoxide, but in a city or near exhaust fumes that can climb to as much as 200 ppm. At atmospheric pressure the first symptoms of poisoning appear around that 200 ppm, and above 400 ppm it becomes life-threatening. Underwater the limit sits far lower. Because the partial pressure of CO rises with depth, the maximum for breathing gas is 5 ppm.
Carbon monoxide is produced by combustion, for example by a compressor with a petrol engine, a generator, or a boat's engine. If the intake of the compressor that fills your cylinder sits close to such an exhaust, and the compressor filters do not remove all of the carbon monoxide, it ends up in your cylinder. Accidents involving CO poisoning among divers have unfortunately happened in the past.
If you analyse your breathing gas with the Echo and the CO value is above 5 ppm, the device sounds an alarm and a warning appears on the display. If the value stays below that, you cannot read the exact CO measurement on the device itself, but it is always available in the Divesoft app. There you see a green bar showing that the gas quality is fine. Tap it and you see the actual value. If it goes above 5 ppm, the app shows the alarm too.
One thing to keep in mind: clean gas reads 0 ppm CO. On a normal measurement you therefore see no carbon monoxide, and so no confirmation that the sensor is actually responding at that moment. The Echo does warn you if the CO sensor is missing or not communicating properly, but that is different from knowing it actually reacts to CO. Divesoft therefore recommends a bump test: you briefly expose the sensor to a known amount of carbon monoxide and check that it responds and that the alarm goes off. Do that now and then and you know for sure that your CO measurement is not just measuring, but actually working.
One of a kind, and in its price class too
Within the Divesoft line the Echo is the first analyser with a CO reading. Stand-alone CO testers and trimix analysers for oxygen and helium have been around longer, but none of them measure all three gases in one device. Devices that combine oxygen, helium and carbon monoxide are almost non-existent. The few exceptions are large, fixed multigas units for filling stations, and those quickly cost a few thousand euros. The only one that measures all three at once, the Nuvair Multigas Color Alarm, is priced on request only. The next "cheapest" multigas alternative, the Nuvair Pro 4 Warn Plus at around $6,122, does not measure helium at all.
It comes down to this: a compact, portable analyser with an app that measures nitrox, trimix and carbon monoxide in one device, for the price of an ordinary trimix analyser, is more or less unique right now. In that segment the Echo stands practically alone. And if you want carbon monoxide measurement within the Divesoft range, the Echo is your only option.
The CO sensor is a separate sensor that lasts two years. After that you have it replaced at a Divesoft service centre. Keep that in mind for your maintenance.
Two oxygen sensors: galvanic or solid state
For the oxygen measurement you choose between two versions, and for many buyers that is the most important decision.
The galvanic sensor is the proven technology we have used to our satisfaction for years. It works like a kind of fuel cell that slowly consumes itself, which gives it a life of roughly 1 to 2 years. Replacing it is simple and you do it yourself. A new galvanic sensor costs €84.95 with us. The downside is the limited life and the sensitivity to temperature swings and humidity.
The solid-state sensor is the new option. Because it works differently, it lasts far longer than the galvanic sensor. Divesoft puts it at 10 years or more, and the sensor's manufacturer even mentions a life of up to around 15 years, depending on your use. It also has built-in temperature and pressure sensors that correct the reading automatically, which makes the sensor more stable and less affected by temperature and moisture. This sensor is user-replaceable as well.
Worth knowing: for the oxygen measurement Divesoft gives the same specifications for both versions. A measuring range of 0 to 100%, a resolution of 0.1%, a T90 response time of about 5 seconds and an operating temperature of 0 to +45 °C.
When is solid state worth considering? In short, if you use the analyser for a long time, say 10 years or more, or if you replace the galvanic sensor often. Replace your galvanic sensor every year and over a 15-year period you quickly pass €1,000 in sensor costs. Do it every two years and you land around €595. The solid-state Echo costs about €450 more to buy and asks for a single sensor replacement at the end of that period. If you dive a lot and keep your gear for a long time, the maths tips towards solid state. If you use it now and then, galvanic remains perfectly defensible. Note: Divesoft's official price for the loose solid-state sensor is not yet known. In a few European webshops the DiveO2 sensor sells for around €400.
Smart with the Divesoft app
The Echo really comes into its own together with the free Divesoft app, which you can download for Android and iPhone. The app shows the readings in a more detailed overview and includes GasBlend blending tools and a best-mix manager to plan your blends. You can also print an analysis label with it. The app creates an ordinary PDF for that. Divesoft mentions the Zebra label printers, but because it is a standard PDF, you can just as easily print the label on any label printer that supports printing from your phone. A Brother label printer that connects over wifi works fine, for instance. Printing directly from the Echo itself, without a phone, is planned for a future update. A date and the supported printers are not yet known.
One note: the iPhone app currently has a small bug. If you connect to the Echo while the menu is open on the device, the app asks you to calibrate the sensors, but the start button does not respond and the confirm button stays greyed out. Closing the menu on the Echo does not help. You have to close the menu, fully quit the Divesoft app and reconnect before it works. Probably a bug that a future update will fix, but right now you run into it. We could not test it on Android because we do not have an Android device.
The four versions of the Echo: which one suits you?
The Echo comes in four versions. You choose between a galvanic or a solid-state oxygen sensor, and each version is sold on its own or as a set with the Professional flow limiter MK2 (DIN G5/8). That flow limiter provides the right flow during analysis and protects your sensor from damage caused by too much flow. A set is cheaper than the separate parts together.
| Versie | O₂-sensor | Inhoud | Prijs |
| Divesoft Echo Analyser | Galvanisch | Analyser + sensor + USB-C-kabel + EVA-koffer | € 950 |
| Divesoft Echo Analyser Set | Galvanisch | Echo + MK2 flow limiter | € 1.049 |
| Divesoft Echo Solid State | Solid state | Analyser + sensor + USB-C-kabel + EVA-koffer | € 1.399 |
| Divesoft Echo Solid State Set | Solid state | Echo Solid State + MK2 flow limiter | € 1.529 |
All prices shown are our prices at The Stage Bottle, including 21% Dutch VAT. If you do not have a flow limiter yet, a set is almost always the smarter choice. On its own the MK2 flow limiter costs €215, plus €23.95 for the connection hose you need.
Solid state mainly makes sense if you analyse a lot, or often work in conditions with high humidity.
In practice: our first impressions
The Echo is operated with a single button. A long press opens the menu or confirms a choice, and short presses move you to the next item. Turning it on is one long press, turning it off takes two: first open the menu, then confirm the shutdown. The operation is intuitive enough, but in practice we find that single button more cumbersome than the multiple buttons on the Solo and the He/O2, where you switch faster. You do more pressing to navigate the menu, and the navigation only goes forward. You cannot step back a level in the menu, so you have to cycle all the way around.
The display deserves a note. With enough light the TFT-HR display reads fine, but it has no backlight. You get either black text on a light grey background or white text on black, so in a dark environment you need a torch to read it. The OLED display on the Solo and the He/O2 is easier on that front.
The EVA case is fine for personal use and travel, and protects your analyser in transit. If you use your analyser mostly on the boat or intensively in a dive centre, a more rugged, waterproof solution may suit you better. We go into that in our comparison between the Echo, the Divesoft Solo and the He/O2 blender kit verder op in.
Who is the Divesoft Echo for?
The Echo is a good fit for technical divers who regularly dive nitrox and trimix, for gas blenders, and for dive centres that check their nitrox and trimix fills carefully and want the extra CO measurement as a safety margin. If you want carbon monoxide measurement within the Divesoft range, the Echo is simply your only choice. After that you choose based on your use: the galvanic version with a lower entry price and a sensor you replace every 1 to 2 years, or the solid-state version with a higher entry price but years of low maintenance.
Conclusion
The CO measurement is the real innovation in the Divesoft Echo. It is a safety check you did not casually run alongside your trimix measurement before, and it fits exactly how gas analysis should work: all the relevant information in one measurement, before you get in the water. On top of that, the choice between a galvanic and a solid-state oxygen sensor gives you the room to match the device to how often you dive. If you do not have a flow limiter yet, go for a set. And if you want the full picture with the comparison between the Echo, the Solo and the He/O2, keep an eye out for our next blog.
Frequently asked questions
Does the Divesoft Echo measure carbon monoxide? Yes. The Echo has a separate CO sensor that measures the carbon monoxide content in your breathing gas. Above 5 ppm the device gives an alarm. You can always read the exact value in the Divesoft app.
What is the difference between the galvanic and the solid-state version? The oxygen specifications are the same. The difference is in the sensor. The galvanic sensor lasts 1 to 2 years and is cheap to replace. The solid-state sensor lasts 10 years or more, is more stable and less affected by temperature and moisture, but costs more to buy.
How often does the CO sensor need replacing? The CO sensor lasts two years and is replaced at a Divesoft service centre so the measurement stays reliable.
How do I know the CO sensor is working? Clean gas reads 0 ppm, so on a normal measurement you see no CO. The Echo warns you if the sensor is missing or not communicating. If you want to be sure the sensor actually responds to carbon monoxide, Divesoft recommends a bump test: you briefly expose the sensor to a known amount of CO and check that the alarm goes off.
Does the Echo work with the Divesoft app? Yes. The Echo connects over Bluetooth to the free Divesoft app for Android and iPhone. It gives you a detailed overview of your readings, blending tools and the option to create an analysis label.
Can I print labels with the Echo? Yes, through the app. It creates a PDF that you can print on almost any label printer that supports printing from your phone. Printing directly from the Echo itself is coming in a future update.
Is the Echo suitable for nitrox and trimix? Yes. The Echo analyses both nitrox and trimix blends, with an oxygen and helium measurement from 0 to 100%.