If you've had the juice in a tank, do NOT put it back into the bottle mixing the fresh juice with the used. The juice in the tanks have gotten heated a bit from the coils. After you've been vaping on it for awhile you'll notice the juice getting a little darker, a little...not tasting quite like you'd like. That's when you'll want to dump it out, rinse the tank well, possibly change the coil to a new one and refill with fresh juice.
You'll want to get more tanks as the wicks inside (even if you can't see them), do tend to hold onto the flavor previously in the tank. Back ups! And back ups of back ups are a must with vaping. You'll never be sorry you got them.
18 mg of nic is around a medium flavored cigarette with 12 being the lights and 24 the full flavored. These are just very loose guidelines. I used to smoke Marlboro Lights (12 mg), about a pack a day when I switched to vaping. At first I needed the 24 mg juice just to get me started and then I gradually stepped it down. These days I go from anything between 24, mostly 12 - 6 mg -- sometimes even 0 mg.
