Hello Ohgrlord, and welcome to the forum.
Could you describe what method you are using to refill your tank? Are you pulling the cartomizer downward from the tank and filling it through the hole in the top end cap (preferred method)? Or are you removing the top cap entirely, filling the tank, and then replacing the top cap (NOT recommended)?
The second method I described above is not recommended because when you replace the top cap onto the tank, there is too much pressure created inside the tank. The pressurized juice has no where to go but into the cartomizer, resulting in too much juice and flooding.
Too strong of a vaping technique can also cause flooding. The best technique with a cartotank is like sucking on a straw in a thick milkshake. Take a long, slow, gentle draw of 3 - 6 seconds.
It sounds like the cartomizers that you are using might be Smoktech. This brand has a looser filler material which may cause them to be more likely to flood. If the above methods described do not help your flooding issues, try using some Boge XL cartomizers which have a denser filler and not as likely to flood.
I've written a few articles on cartomizers and cartotanks in my blog. You may find some useful information there; in particular a cartotank tutorial and a large list of online vendors that sell pre-punched cartomizers.
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