How do I know when Duo Pro cart is empty?

[azeis]

I just got a Duo Pro from electonriccigarettesinc.com and love it so far. My question is how do I know when the cart needs to be changed? I let it run down so I get very little vapor out of it, but it doesn't seem to run out completely. Do I use it until there is no more flavor or there is a noticeable loss of vapor? Any help is appreciated. Thanks much.

 

[Kurt]

Cartomizers tend to let you know they are done when the vapor drops off a lot with a fresh batt. Putting a known fresh carto on, will further tell you the old one was done. That said, it is possible to add juice to the carto, although it might take some experimentation to get it right. People either drip in through the battery end, or pry the mouth-cap out and add to the filler roll from that end. There is an art to it though, so practice makes perfect.

 

[DonDaBoomVape]

I wouldn't let it run down too much. Once a cartomizer dries out, it may be a lost cause to try to make it taste good again. I'd suggest refilling as soon as the vapor drops off a little bit, and then...

The refill method, which has wowed the cartomizer community is Dogbody's carto cap refill (or "condom") technique, e.g., as demonstrated by Doctor Vapor:

YouTube - A Great Way To Fill Cartomizers​

BTW, there are many other (less expensive) suppliers of the Kr8 model and cartomizers for it, often sold under different brand names (as does Electronic Cigarettes Inc.). Just in the U.S.: Vapor4Life (Vapor King), NHaler (KR808D-1), AltSmoke (KR808D), CigEasy (Easy), Cigtechs (KR808D), GoodProphets (VapoRite), LeCig (D1), Liberty Flights US (KR808D-1), LiteCigUSA (KR808D-1), Mist-Stix (Mist-Stix), PureSmoker (Ace), The House of Vapor (KR808D-1), VaporKings (KR808D-1), and VaporNine (Nebula).