Sorry for the n00bish question, but hopefully someone will be able to help.
OK, here are the basics;
I have a VV Halo Triton, and I am using the Triton tanks with the stock coils. I keep my VV dialed all the way down (3.3V) for the juice I am having issues with, because it tastes better with a cooler coil. The juice is Halo's Voodoo in 24mg, lot expires 10-22-2014.
I don't take big hits, but I hit it a lot. Early in the day the juice tastes normal, and the color is the same as the initial juice. But near the end of my work day I see the juice has changed color, it is significantly darker, and it tastes almost burned. I thought it was my imagination, but I tried it for a couple days and it is not my imagination. I also noticed that I see some vapor in the tank as well and I don't recall seeing it early in the day. The wicks do not appear burned. When I topped it off in the morning (I am vaping roughly 2ml of 2.4mls in the tank, so I have roughly .5ml remaining) and it tastes fine. You can actually see the darker juice blend with the new juice.
I have several Triton tanks, and they are all filled with different flavors and I don't have this issue with anything else. I have also used my G6 (Halo cigalike) with a mini tank and the Voodoo and I don't experience this issue. Can anyone shed some light on what may be occurring?
I have roughly 2-4 tanks of Voodoo loaded at any given day. Towards the end of the tank, like 1/4 left, I too can get an occasional burnt taste. I also have Halos VV and use their tanks. I find I get this if I chain vape or don't let the wicks cool enough in between vapes. You might want to try a diff ohms just to test out too. I usually vape it around 4.3 without getting burnt taste unless, again, it's down to like a 1/4 tank and has been loaded for about a week.
I also recommend bringing extra tanks of other juices with you to work and rotate out. Thats another reason why i have so many Voodoos loaded so one tank/coil isnt taking all the hits. I also top off my Voodoo tanks when they're about 1/2 gone for "fresh" juice, then clean tank and coils at least once a week. If you see burnt spots on the top wick, its toast.
I wouldn't say Voodoo is a coil gunker, but it is a thicker juice and a lot of juices change color, even steeping I've had juices go from clear to dark without even vaping, so color change is normal. Voodoo gets a deep brownish red when its aged in a tank. Not sure if this helps at all.