Having had IBTanks, you'll likely be disappointed in the quality of the Smoktech pyrex DCT tanks. The end caps are fixed and can not be removed for easy cleaning of the tanks, and the o-rings can not be replaced. The o-rings are not as good of quality, so the tank may slide too easily off of the carto if you're not careful.
Other than the above cons, these are a decent gateway into novice-level cartotanks. My
A much better option, since you already have cartomizers for your IBTanks, would be the Smoktech polypropylene DCT tanks ($8.55) from
My Vapor Store. These have removeable end caps, are safe for all flavors of e-liquid, and with better quality o-rings which prevent the tank from sliding off the carto.