Cthulhu RTA III, the beast walks the earth

What’s up vapers!
SirRisc here with another gear review!

This Cthulhu RTA III was sourced from Cthulhumod!


Ah, Cthulhumod. One of the few brands that always gets me curious as to what they will come up with next.
Because really I have to hand to these guys, they are clever in the way they can take an existing design and improve upon it.
And not just that, they tend to have some very original ideas of themselves too. Just look at the Shuriken RDA and the way the airflow is handled on it.

But I digress… The first device I ever owned from these guys was the Cthulhu RTA V1, and it was an eye-opener.
It had a fairly well built deck, it had a massive airflow, and it worked better than the Subtank which was being hyped by everyone and their dog at the time.
It remained in my rotation for a long time, until it got replaced by something bigger and better. You all know how it goes, right?
The Cthulhu RTA V2 is one I never got, mostly because I heard from several people that it was overengineered and needlessly complicated.
Despite that I kept following their work, and when I saw that the Cthulhu RTA V3 was released I got very curious again.

So how does the Cthulhu RTA V3 measure up?
Let’s find out, shall we?

Cthulhu RTA III


  • Stainless steel (SS304) and glass construction
  • 24.5mm base, 26mm diameter
  • Two decks included; dual coil Velocity styled deck and single coil, both measuring 19.8mm
  • 3mm wireholes, made for big builds
  • Top refill system
  • Liquid flow control
  • 5ml capacity
  • Big airflow holes
  • Two-step chimney for improved flavor
  • Available in stainless and black


The Cthulhu RTA III comes in a rather simple yet stylish white box.
The days of the plastic container in which the first iteration came are long gone, and this does look a fair bit better.
On the front of the box you’ll see a wireframe of the RTA itself, and the two decks that come with it.

On one side you’ll find the Cthulhumod logo, which I still find one of the best looking ones on the vaping market.
The other side has a short listing of the RTAs strongest points.
The back of the box holds the full specifications of the Cthulhu RTA III, as well as links to their website and social platforms.
There’s also an authenticity sticker with a scratch n’ check.

Opening the box reveals the usermanual with the RTA and accessories underneath in a black foam insert.
The usermanual is short and sweet, but very well illustrated.


Let me start off with this fact; if you’re looking for a stealthy vape, this will not be an RTA for you.
The Cthulhu RTA III is a big tank with big airflow and big decks. The decks are made for big coils that cause big clouds.

With that out of the way, let’s look at the RTA a bit closer.
The RTA has a base diameter of 24.5mm, which means it fits on most boxmods without overhang.
However Cthulhumod opted to widen the tank just above the airflow ring to a diameter of 26mm.
This causes the tank to look bigger/bulkier than it truly is, but it also allows the decks to be wider and allow for bigger builds. Of course this also means it has a bigger capacity, which comes in at 5ml.
The decks, because there are two of them included, measure a whopping 19.8mm in diameter. This is on par with the latest generations of RTAs and even some RDAs.

The RTA features a large glass section sitting on white o-rings. Black o-rings have been included in the packaging, so you can switch them out if you so prefer (which I did).
The body itself is made from 304 food-grade stainless steel and comes in two colors, stainless steel and black.
Inside of the RTA we find one of two decks, a rather short two-step chimney which slightly enhances the flavor and juiceflow control capable of being set for single coil builds (depending on the deck you’re using).
On the chimney you’ll see the Cthulhu logo, which in my opinion could have been slightly more pronounced. To each their own, I just love the logo.
The topcap can be removed to reach the topfill section of the tank, two very large kidney-shaped holes make it extremely easy to fill.
One thing I notice is that most RTAs tend to leak through the airflow when you fill them without closing the juiceflow control. The Cthulhu RTA III doesn’t, I’ve filled it dozens of times and it has yet to leak.

On to performance! How cloudy does it get?
Well, very cloudy really. Even with a single coil build this tank doesn’t screw around.
The Cthulhu RTA III comes with two decks, a dual coil one with a Velocity styled deck that is implied to be made for cloudchasing, and a single coil one that is implied to be a flavorchasing deck.
Both decks are spacious enough to allow for coils with a larger inner diameter than usual, up to 4mm is perfectly possible without touch the barrel.

The dual coil deck is a Velocity styled one, two posts with two holes each for easy building.
The holes measure in at 3mm so you can fit some pretty bulky wires in there.
For example I’m running a staggered fused clapton build in this deck with 26AWG cores and 34AWG wraps and I have room to spare in the holes.
The wicking is very straightforward and more forgiving than I expected. With juice channels rivaling the size of the Panama Strait it does need quite a bit of cotton to fill, but it also has plenty of room to tuck that cotton in.
Cutting the wicks to just drop down into the channels seems to be the best way without dryhitting or leaking.

The single coil deck is another matter entirely and is a lot less forgiving.
The size of the deck is the same as the dual coil deck, but it has a more Kayfun-esque construction.
What this means is that your coil will sit dead center of the deck and fit under the screws. It will still allow you put a bulky wire underneath but definitely less bulky then on the dual coil deck.
The juice channels are a bit smaller since it only has to feed a single coil, yet they are still large enough to tuck a big piece of cotton in there.
I’ve tried a couple of builds on this deck and have to admit it’s an extremely easy deck to build on.
The first builds was staggered fused clapton with 26AWG cores and 34AWG wraps which fit fine, the second build was a juggernaut with 26AWG cores, 34AWG and 0.1x0.5 ribbon wraps.
That second build was a bit harder to fit underneath the screws, which caused the build to heat up unevenly.
After a couple of frustrating moments of taking the deck apart, tightening the screws and strumming the coils with a screwdriver, it eventually started heating up evenly.

In terms of experience I definitely prefer the dual coil deck, but the single coil deck is definitely more suited for flavorchasing.
Despite that the RTA is mostly geared towards cloudchasing, even with the single coil deck the flavor isn’t as strong as some other RTAs.
This doesn’t mean the flavor is weak, it just isn’t as pronounced.
Closing the airflow down by half does bring a lot more flavor to the olfactory.

This brings me to the airflow, it’s huge. And when I say huge, I mean it’s as if you’re breathing through the tank without any resistance.
That does make the tank suffer from loss of flavor, and that’s also why closing down the airflow to about half is advisable.
If you’re really adamant on cloudchasing, you can leave it open and enjoy a weaker flavored hit that has its own weathersystem.

The driptip is something I’d like to mention briefly too.
It’s not a standard 510 driptip, but rather a widebore delrin driptip with the same measurements as the Griffin driptip.
Unfortunately I lost my driptip a couple of times because it’s extremely loose, the o-rings seem to be too thin.
I solved this by taking to o-rings off, applying a layer of teflontape and then putting the o-rings back on. (This is perfectly safe considering the teflontape is sitting on the outside of the driptip and doesn’t come into direct contact with the juice or the vapor)
Cthulhumod does include a 510 driptip adapter for you to use your own driptips.

There’s one thing I don’t like about the Cthulhu RTA III, and that’s the black hole they snuck into the tank.
Allow me to explain… The RTA has a capacity of 5ml, but the juice disappears so damn quick that I’m starting to suspect there’s an actual black hole in there sucking the juice out.
It’s anything but a frugal tank, 5ml feels more like 2ml but it does provide a full and dense vapor.

Overall the Cthulhu RTA III is a beast, it rivals the performance of RTAs like the Limitless XL, the TFV8, the TF-RTA, it even challenges some drippers.


The Cthulhu RTA III isn’t the best looking RTA out there, but it’s definitely not an ugly one.
The fact that it widens to 26mm does make it look bulky, but it fits on most boxmods because of the 24.5mm base.
The airflow ring sits rather loose and the topfill can be a bit of a bitch to open sometimes, but the RTA makes up for it in its looks.
Machining is done extremely well, there are no sharp edges, no flaws, not even a trace of machining coolant residu to be seen.
It’s clean out of the box, and that’s something Cthulhumod have gotten remarks about in the past.

As I said above the logo is, in my opinion, one of the coolest ones out there.
I’m quite a fan of Lovecraftian literature and having the depiction of Cthulhu on the chimney does have its charm.
That said I think the laseretching could have been made slightly deeper to bring it out a bit more.
On the black version, which I don’t own (yet), the logo is a lot more defined and visible. The stainless version however doesn’t show the logo off like it should.

Pros and Cons.


  • Clouds, bro!
  • Two big decks included, a dual coil and single coil
  • 5ml capacity
  • 24.5mm base but 26mm diameter
  • Easy topfill (huge holes)
  • Ph’nglui mglw’nafh Cthulhu R’lyeh wgah’nagl fhtagn.


  • Drinks juice like a black hole swallows mass
  • Top fill can be hard to open (topcap knurling is fairly smooth)
  • Airflow ring is rather loose
  • Driptip is way too loose

In conclusion.

The Cthulhu RTA III is the latest iteration of an already great line of RTAs.
Including two decks is definitely a good move by Cthulhumod as it provides a very different experience with either of the sizeable decks.
There’s plenty of room to build bulky coils and the airflow allows for those bulky coils to be cooled down pretty fast.
The flavor could be a bit more pronounced from the RTA, but it’s not bad at all. It’s just not as strong as some other RTAs.
If you’re looking for a cloudchasing RTA, this would definitely be a good choice.
Would I buy another one if this one broke? I’ve already got a black one on the way, 'nuff said. :wink:

In closing I would like to thank Cthulhumod for sending out the Cthulhu RTA III!
Thanks for reading, join me next time as I take a look at a few bits and bobs from Coilmaster!

Need to reach me? Head over to my website.
Interested in what I vape daily? Check out my Instagram.
Want to know more about DIY? Head over to ELR.

#staycloudy !

SirRisc disappears in a cloud of vanilla custard and lemon scented vapor

DISCLAIMER: This review is based on personal opinions and is not intended as a promotion, endorsement or advertisement.
The publisher is not sponsored, affiliated or compensated in any way.


Nice write up and review! :grinning:

I’ve always loved my Cthulhu tanks, especially my V2’s; coming with two build decks was the selling point for me. :wink: I was sad to see the V3 had a 24.5mm base, but that’s the way things are going these days…bigger, bigGER, BIGGER! :speaking_head:

Just about every mod I own is sized for a 22mm base and I want to keep it that way. :triumph: