Many people have problems with getting good flavor on Ego tanks, LR or not. I don't use tanks. I just see what other people say about their tanks.
Cartomizers are disposable combined cartridge + atomizer. They have limited lifespans, you can not replace the stuffing. Each cartomizer has its own atty so your flavors are totally separate. Standard stuffing-type cartos with soft caps require no syringe to fill and typically hold about 1ml. There are some jumbo cartos too. There are also reservoir cartos with no stuffing that need a syringe to fill (some need blunt or flexible, some need sharp) and the clear versions of these can crack and fall apart. There are also sturdier clear versions people make and sell using a plastic bottle or syringe as the sturdier body cylinder material and the atomizer/wicks out of a CE2 reservoir carto and these are called MAP tanks and ARRY cartomizers, CE2 bottle mods (you can see one example at NiteliteVapor). I have never used these either. I just use plain old Boge cartos, the most popular cartos for 510 threading.
Only put juices you like in cartomizers. Only some succeed at cleaning and drying them and most don't bother. I get the longest good use out of a carto with thin clear juices, 20% or less VG juices and I look for ones that leave little or no flavoring sediment (typically lighter clearer juices). I vape 1/2 the time on my Boge 510 carto (I use standard resistance so my slim 510 battery can use it too) and I can get 2-3 weeks use out of a Boge if I vape it 1/2 the time, and sometimes 4 weeks though by even the end of the 3rd week it has degraded noticeably. I am just cheap haha.
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How I fill a cartomizer (Vapor4Life for KR8 or Boge 510 for 510 which are all soft-cap w/ no inner seals and defined central air channel)
I use thin (20% or less VG) liquid or Vapor4Life WOW liquids, preferably clear liquids w/ no sediment
Filling a blank carto - I pop off the soft cap (unbent paperclip carefully in the mouth hole, not catching any wires or stuffing!). I hold some tissue against the threaded end hole. I tilt the carto and slowly drip 18 drops onto the inner wall of the carto so it slides down into the stuffing while I rotate the carto. Then I wait 15 seconds or so then I drip however many more drops the stuffing wants to soak up. Then I do clean-up. If it is leaking, I clean that up. Then I tilt the open end down into the tissue and puff hard a few times into the threaded end to clear any juice out of the central air channel (I want to see light through there). If it looks too wet above the stuffing, I gently touch a bit of tissue to the stuffing (otherwise that liquid will be gurgling or spitting in my mouth). Then since this was a fresh fill of a blank, I now let it settle. I lay the carto on different sides for 15-20 minutes. Then it should be ready to vape. If you use thicker juices than me, then you may need to let it settle longer.
As I am vaping - if the vapor gets a bit light or a bit dry or tastes bit off or the carto is getting unusually warm, I will take the carto off the battery, open it, add 6-8 drops or whatever it seems to want (I will either hold a bit of tissue against the threaded end hole just in case, or skimp on how many drops I add to make sure I avoid drips if I have no tissue). I check to make sure the threaded end is dry, give it a couple of puffs into the threaded end to make sure the air channel is clear, and continue to vape.
Note - it is easy for me to "open" my main cartos for adding juice because I replace the white end cap with a plastic or delrin drip tip (I get them at LiteCigUSA.net). So I can easily pull that out with my fingers when I add juice and it keeps my lips cool if the carto is hot.
