How to Prefill a Cartomizer and Fill a Cartotank
Filling, or Priming, the Cartomizer - "Drip & Flick" Method:
This is the method that I have used successfully. To keep juice out of the center air hole when filling the carto I plug it with a wood tooth pick: Using a Tooth Pick in a Carto During Priming
The most important step is to completely fill the carto with enough juice. How well you do this step will determine how well this carto will perform for the rest of its life in the tank. Take your time & do it right.
I hold the carto at a slight angle, and gradually spin it around as I drip liquid onto the polyfill. When the fibers are wet, I flick the carto down like a thermometer. Hold the carto from the top & flick it forcefully toward the floor a few times (keep holding onto the carto, silly) . This produces the same effect as a centrifuge, forcing the juice down into the bottom of the wick of the carto.
Then add more drops, and flick it down again. Repeat this process until the polyfill will absorb no more liquid. The fibers should glisten like a slushy drink; saturated but not pooling on top. Now the carto is ready to be put into the tank.
* I don't count drops; different size droppers make different size droplets and can throw your volume way off. 35mm carto will hold 1 ml; 45mm carto will hold 1.5 ml.
Filling the Tank:
Your tank should be completely assembled with both end caps on the tube. I replace the tooth pick now with a tank tool as shown in the PBusardo video in this blog article. The tank tool has multiple uses, but here it keeps too much e-liquid from getting into the carto. At this point, you are only filling the tank. I lubricate the tool and carto with a little bit of e-juice and insert the carto about half way into the tank through the bottom end cap. I then fill the tank about 80% full of juice through the hole in the top end cap.

Now I'm ready to gently "twist" the carto all the way up through the top cap, while also securing the top cap with my other hand to be sure not to allow the cap to be pushed off the tube. The tank tool helps guide the carto through the cap. Now remove the tank tool and replace it with a drip tip. It's now ready to vape.
How to Refill a Tank:
To refill a set up tank with more juice, I remove the drip tip, insert the tank tool onto the carto, and while securing the tank's end caps, I push downward on the tank tool so that the cartomizer slides halfway through the tank. This allows enough space to add more liquid through the top of the tank. Once refilled, again still securing the end caps with my other hand, I gently twist the carto back into position. Remove the tank tool and replace the drip tip. (You need not add juice to the carto during refills, but this is optional)

______________________
The following is the best video demonstration I have found that shows how to fill a cartomizer and cartotank that uses most of the methods I practice. Keep in mind I use the tooth pick and the Slap Yo Moma tank tool in addition to what you see in this video.
How to "hot swap" cartomizers in a tank that is still partially filled with juice
(Special thanks to The Ocelot)
______________________
Cartomizers in a cartotank can last for 1-3 weeks depending upon how heavily it is used, and how
dark/thick the juice is. Darker and thicker juices will eventually cause the polyfill in the carto to become clogged, resulting in flavor loss and a stiff pull when vaping. A cartotank can be refilled multiple times with the same carto in place. Spent cartos are discarded.
Slap Yo Momma - Best Tank Tool Ever !

I highly recommend all cartotankers to obtain a tank accessory tool. I find having one of these tools to be indispensable if you use cartotanks. It simplifies and speeds the assembly and filling of your tanks, and best of all using one will protect your tank's o-rings and keep it from leaking from torn or worn out o-rings.
IMHO, the Slap-Yo-Momma tank tool from Big Daddy Vapor is the best designed one. Watch the following PBusardo video review to learn how this tool can protect your tank's o-rings and makes filling your tank with juice much faster & easier.
Why Pre-Punched Cartos for Noobies?
I personally recommend that beginners buy pre-punched cartos because they can provide a beginner a level of consistancy in the size and placement of holes without needing to learn a new skill of punching their own, and using these removes at least one of the potential human error factors in using a carto tank for a beginner.
Once one has some experience with cartotanks, they can then decide to obtain a punch tool and learn to punch their own. Alternatively, they could learn to slot cartos with a powered dremmel tool.
I've been using cartotanks pretty much exclusively for 2 years. I have used both punched and slotted my own cartos. I've personally found making my own holes or slots to be unsatisfactory for a couple of reasons, and have returned to purchasing carto's with the laser-drilled holes made by the manufacturer.
Tool-punched cartos can physically deform the cartomizer's shape from round to oval (see first image below; notice the deformity of the carto's shape). This deformity could possibly make them difficult to fit through the tight round hole in the tank's endcap. The extra effort required to twist them through the endcap puts unneccesary wear and tear on the endcap's rubber o-rings, which prevent a tank from leaking it's liquid contents. You can see this damage in the video of the Slap Yo Moma tank tool in PBuardo's video review previously seen on this page. Cartos slotted with a dremmel can also damage o-rings.
Laser-drilled cartos do not have this issue, and they wick the juice just as well as the larger tool-punched holes in my experience.
How many holes? If given the choice in the number of holes I choose 2. I choose a single hole for juices with a Pg ratio of 70% or more. A Vg ratio higher than 70% I choose 3 holes. This has worked great for me.
Dual vs Single Coil Cartos: My Experience
You can use either single or dual coil cartos in any cartotank. Some cartos have a flange (lip near the connector end) which fits into tanks made by Smoktech, but a flange is not really necessary.
After having used dual coil cartomizers exclusively in my tanks, I had become somewhat dissatisfied with them with an occassional burnt taste with my e-liquids. I did some research into dual coil vs single coil cartomizers on ECF.
What I found were mostly opinions. Many people had switched from duals to singles, arguing that the dual coils didn't produce enough benefits to warrant the additional drain on battery life. There were others that preferred dual coils for their warmer vape.
There were statements made that dual coils were developed to be able to provide more vapor production for fixed voltage PVs, via twice the number of coils within the cartomizer. However, there were skeptics to that statement who claimed that for a dual coil to really shine, voltages of 4.5v and higher were required. Contradictory theories? I thought so, too.
Long story made short, I decided to give single coils a trial. I switched out all of my tanks to single coils...same brand, same ohm resistance, same number of holes. The verdict: I was and am impressed with the single coils. Same vapor production and flavor, no more burnt taste, and the expected increase in battery life. Your results may vary from mine.
My theory with dual coils is the upper wicking area is the first to become dry, allowing the top coil to burn the wick. Dual coils seem vulnerable to experience dry hits more often than single coil cartos.
The upper top coil in a dual coil would be in the area of the number 5 above. Note how as the carto is used the liquid level will fall below that top coil and probably result in a burnt taste.
What Ohms or Resistance Carto Should I use?
This is determined by personal experience after sampling low and standard resistance cartos. In general if you are using a fixed single voltage device (mechanical) low resistance cartos are used. If using a regulated variable voltage battery, standard or high resistance coils are used.
Keep in mind that low resistance cartos burn hotter and use more battery energy. Standard or high resistance cartos will provide a cooler vape and allow a wider range of voltages to use, and be kinder on battery usage.
Lower Ohm Coils Will:
- Heat The Coil Faster
- Produce More Vapor
- Drain The Battery Faster
- Use E-Juice Faster
- Produce A Warmer Tasting Vape
- Heat The Coil Slower, Which Will Produce “Less” Vapor
- Provide A “Cooler” Tasting Vape
- Use Less E-Juice
- Prolong Battery Life
Safe Vaping Power Chart
