March 20, 2018

ByLeo Calix V4

Category RTA
Manufacturer ByLeo EU
RRP €109.99
Diameter 22mm
Height 39mm


The Calix V4 as it arrives to you, in the box I purchased the Calix V4 shortly after it was released directly from byLeo in Greece, I have serial number 0016. It arrived in London well packaged in about 5 days by FedEx.

I vape either 50vg or 60vg juice in broadly two ways, the first is a tight MTL, with an approximately 1mm airhole using a short one second draw, a lot like how I used to smoke a filtered roll-up. The other is a very restricted lung hit - using about 3mm of airflow. For both of these I prefer a slightly spaced coil with 2.5mm inner diameter, made from 0.35mm (27awg) A1 Kanthal, 6/7 wraps and reading almost exactly 1Ω. I use generally the same builds in all of my rebuildable tanks and it’s with these parameters in mind that I’ll be reviewing the Calix.

I’ll split this review into a few sections based on some topics that are important for me to consider when purchasing a new atomiser. In general order of importance these are Airflow, Overall build quality, tank design and refilling, and build deck design, followed by some general thoughts and conclusions.

Please remember that as with most things involving actual humans, these opinions are entirely subjective and based purely on my personal experiences and vaping preferences.


The airflow under the coil is around 3mm and the airflow ring has 3 holes, the first is 1.6mm and the other 2 are 1.8mm.

Generally the airflow is very smooth, however at it’s tightest setting of 1.6mm and given how I like to vape, it’s a particularly strange draw for me, it’s too loose to be what I’m used to for MTL but not open enough for me to lung hit it.

Whenever I vape it’s almost as if I can’t decide whether I’m supposed to be MTL/DLing it and end up trying to do both simultanously, and unsuccessfully.

The closest it gets to the way I vape is a restricted lung hit with the smallest and half of the second hole open. However having half a hole open introduces a bit of turbulence that I find off putting. Anything wider than that and it’s too open for me, it starts to veer towards full lung hit territory, which is not the kind of vape that I like.

The draw when the AFC is completely closed is a nice comfortable MTL draw, however I have found that having the AFC closed like this changes the pressure within the tank and caused a small amount of condensation to seep from the bottom of the tank when used like this for long periods.

There is a replacement 510 pin for the Calix available which reduces the airhole under the coil to 1.2mm in diameter and can be purchased as an optional extra. I didn’t purchase this pin, which I regret as I suspect that with 1.2mm under the coil I’d have been able to fine tune the airflow to something much closer to my ideal.

Build Quality

Next up, let’s talk about the fit and finish. The Calix is generally a very well built tank, it’s nicely machined and does look nice. All the threading is smooth and fits together well. It arrived free of burrs and machine oil, and there’s no evidence anywhere of tool marks or unfinished machining. The 510 is 4.5mm Long, sits flush on all my mods, and protrudes nicely (this can be adjusted slightly by unscrewing the inner deck).

All parts for the Calix V4 dissassembled for cleaning The Ultem parts (tank, spare top cap, and drip tip) are also of excellent quality, the Ultem is nice and thick and the threading on the tank section feels positive and well machined, with accurate tolerances that make it very smooth to thread on and off the base. The drip tip is not to my taste but, It has an 11mm outer diameter and a 5mm bore. My preference is for an outer diameter narrower than 10mm.

The only thing noticeable by it’s difference in quality is the air flow control ring. The metal feels a little thin and fragile, especially when compared to the chunky, well finished nature of the deck and the chimney section. It stands out against the other components. It’s also fairly loose being held on by a single o-ring. I often find that the AFC ring has moved from it’s setting when I take the tank out of my pocket or bag.

General Operation and Design

The design is simple and attractive, there are a couple of nice grooves in the top cap which help to break up the design aesthetically as well as providing grip for when you need to remove the cap. There is some matching engraving on the AFC ring, which helps to give a sense of symmetry.

It uses typically Greek juice flow control design, where the chimney and chamber is threaded onto the base and controlled by turning the drip tip. It’s identical to almost every tank produced by Imeo (Golden Greek), all the previous Calix tanks and also similar to the Rose3.

It works well, there’s a nice chunky o-ring under the cap (like the Rose3 and the Tilemahos) that keeps the resistance of the JFC smooth, stabilises the chimney, helps keep your JFC setting and stops the juice leaking from between the chimney and the top cap.

It doesn’t have the drip-tip notches that the Rose3 has which is both a blessing and a curse. It does mean I’m not restricted to the supplied drip tip in order to use the JFC which is good as I’m not a fan of the supplied tip. However because you turn the drip tip in order to adjust the JFC any tip you use needs to be a really tight fit, which means most of my tips are useless (thankfully my Kayfun 4 tip works, which is one of my favourites).

The top cap pulls off to fill, rather than unscrews and is held on with two o-rings. Again this is both a blessing and a curse.

It’s good because it avoids the problem that you have with the Tilemahos, the Rose and the Calix V2, where the friction of the o-ring causes the juice flow control to unscrew as you unscrew the top cap, which will potentially cause your build to flood.

However, because the top cap is push fit there’s no way to release the pressure when replacing the cap. This pressure can cause a small amount of flooding, especially if the o-rings are tight, which they were when brand new. They’ve loosened up with time and lubrication so that this is no longer a problem.

I worked around this by pushing the cap over the first o-ring and then inverting the tank and pushing the cap all the way home. I only had to do this when the o-rings were new, now they they’re broken in the top cap pushes on much more smoothly and I’ve not had the same problem for a few weeks.

It was a little dissapointing to have to do this on an atomiser with an otherwise excellent JFC mechanism.

Moving on to the tank section - it’s Ultem, which is fine. I would have hugely preferred glass. I’m not keen on the colour of Ultem and I generally try and avoid plastic where I can because I don’t like having to worry that the juice that I’m using could potentially crack the tank. Ultem, however is far preferable to PC or Acrylic as it’s more resistant to high temperatues as well as acids and alkalies. I still think it looks like piss though!

My biggest complaint with the tank is that it’s threaded. I don’t like threaded plastic tanks. Screwing plastic onto metal is a delicate operation and at some point in the future those plastic threads are going to break. There’s something that really doesn’t sit well with me knowing that the tank section is essentially a consumable and that I’m going to end up needing to spend £10 plus shipping at regular intervals as an upkeep cost.

Now thankfully this tank isn’t bottom fill so you don’t have to unscrew the plastic section it to fill it, which means it’s only getting unscrewed every rewick - which for me, means once every few days rather than multiple times a day. But it’s still not ideal on an atomiser in this price range.

Building on the Calix

A top down view of the Calix V4 build deck with 2 longer screws installed Fans of the Calix series of atomisers will be familiar with the deck design, as it’s basically the same as the V2 and V3, except with the screws moved from the sides of the posts to the top. This, I’m told, was done to avoid having to unscrew the inner base of the deck with every rebuild and prolong the life of the insulating o-ring on the 510 post, which helps to prevent leaking from the 510 pin. A common complaint on previous versions of the Calix. This is my first Calix so whilst this is interesting background I’ve been approaching this RTA as someone new to the Calix system.

The deck is interesting. Each post consists of a large semicircular section with screws in the top, one at each end, so that it doesn’t matter if you wrap your coils clockwise or counter clockwise; you can rest your coil legs on the posts, coil pointing down, and it’ll sit a fixed distance from the airhole. It’s quite nice.

I can see how this kind of deck would have been considered innovative in 2015 when the original Calix was released and a lot of the competition had simple two post Kayfun style decks (the Velocity RDA with it’s namesake deck was only released half way through the year), but in 2018 there isn’t much to differentiate it from other types of deck design.

Tanks like the Cthulhu Hastur MTL (and to a lesser degree the Innokin Ares and Merlin MTL) all look like they’ve taken cues from the original Calix deck design and improved it in various ways. The coil leg slots on the Hastur being an excellent example. In the new Calix we have to wrap our leads around the screws, which makes using thicker guage wire trickier than it can be.

The build is simple enough with 27g wire, although I had to swap 2 of the post screws out. The installed post screws are exceptionally short, and have small heads, trapping anything thicker then 28g wire with these is a pain. They’re also so short I nearly lost one in the carpet when the tank first arrived, they’re very easy to back out too far.

Thankfully, some longer, and larger screws are provided in the spares bag, so once I had changed the screws over, building with my usual 27g coil was fairly simple. You have to work out which side of the screw to trap your leads so the screws don’t spit out you wire, and remember to install your coil pointing down, but once you’ve got that sorted then it’s a pretty simple build. There isn’t much room to alter the coil placement because of the height of the deck sides, which is a shame as I’d have liked to experiment with pushing my coil slightly further towards the airflow. My usual 2.5mm coil ends up sitting 3-4mm above the airhole when mounted.

There are two methods of wicking the Calix, indirect and direct, based on how far you’ve tightened in the inner deck and where the juice feed holes have ended up in relation to the ends of the wicks. Firstly, indirect method didn’t work for me at all. Even with 50/50 liquid it just doesn’t keep up.

I work in an office where I can’t vape, so most of my vaping is done during my breaks, which means I tend to chain vape for 10 minutes, every few hours. Even at home I spend a lot of time with my daughter so tend to chain a few toots when I can grab a couple of minutes. Even with direct wicking, I had to thin the wick out almost to the point of leaking before it could keep up with my vaping style.

Actually wicking the Calix is a simple matter though, as it’s very obvious where the wick needs to sit, especially when in the direct feed setting.


The Calix V4 RTA on top of a Limelight Pylon SX350Jv2 I’ve been using the Calix exclusively for a little over a month, and whilst I don’t do “fancy” coils, and I have not tried dual, triple or quad-coiling the Calix (all of which are possible with this build deck and some effort), I have used a variety of simple single builds ranging from 0.2mm(32awg)/1.8Ω to 0.42mm(26awg)/0.5Ω.

I found that due to the length of the deck, the Calix really shines with slightly larger coils than I normally go for. I had the best results with a 0.7Ω 26ga spaced coil with a 3mm diameter

The Calix V4 is a great little tank, well made and solid. It looks good and performs well, and it’s a real shame that I haven’t been able to make it fit my vape style without issues as it’s delivered. I suspect that this would be solved with the MTL reducer which is available seperately.

It has a few small cons that will always prevent me being truly happy with it: a threaded plastic tank, loose AFC and a build that I find a touch more challenging than others, and I wish the MTL reducer had been included in the package (possibly instead of the Ultem top cap, which I dislike the look of and will never use).

If Ultem is your thing, and you like a loose MTL or restricted lung draw, and prefer slightly bigger coils than me then you can definitely do far worse than the Calix V4.