Just thought I would add a little more to the conversation regarding nicotine level. OP, what is your underlying reason when you originally said you needed a lot of nicotine? We know that the tobacco industry is heavily regulated and the typical cigarette contains between 1 and 1.5mg of nicotine. That makes 20-30mg per pack. If you smoked the whole pack, realizing that only 10% of the nicotine in the cigarette is actually absorbed, that means out of a pack of cigarettes you are absorbing between 2 and 3mg of nicotine. At 18mg e-liquid strength, while there are no hard-and-fast numbers like there are for cigarettes (if there are, someone please point me to them!), my educated guess would be 3-5% of the nicotine in e-liquid is absorbed. At 5%, that means a 0.9mg/ml nic is absorbed, so a 3ml tankful of 18mg e-liquid yields the same nic absorption as a pack of cigarettes.