I bought an Aspire Evo75 at the advice of my local vape shop. I have used older style 510 pens with atomizers and then clearomizers later on, but before these non DIY mods were common. I have never had any issues with the 510 stuff, other than some quality issues from time to time. With my Aspire Evo75, I have used both the .5 ohm Aspire Atlantis Evo coils, and tried .5 ohm Aspire Atlantis (non Evo) coils because I don't really need that much wattage to be satisfied. I only use the non Evo coils in the extended tank so even though they probably wouldn't work in the short tank, they work great in the small tank. The issue I have been having is the fluid seems to burn after approximately 12 hours or so, maybe a bit more. The coil does not seem to be burnt, and doesn't taste burnt (I know what that tastes like), it's much more subtle and I can see the fluid go from virtually clear, to either a light brown, or if I keep using it, a dark brown. If I drain the tank, and just replace the fluid, I still get the same results. The taste just gets worse, it doesn't actually taste burnt, it almost tastes more like the fluid is getting caramelized. For example, I use a strawberry lemonade flavor that is pretty crisp and tart, but once it starts to burn, it tastes sugary at first, then starts to have a burnt taste. The flavor will eventually just not taste good, not really a burnt taste, but kind of, just a worst taste and the coil seems clogged. After I use a coil, I clean it and it looks brand new. I really don't think I am burning the coil, the cotton is totally white and looks almost like it is new, just slightly "looser" and the coil is still shiny and clean. The fluid I use is from a local place called Tasty Vapor in Oakland. I have yet to try other fluid so far as I try to shop locally. I do know it is sweetened and I can buy it unsweetened as well. I have used both 50% VG and 70% VG, I like the second better, both have the same results. I understand that the higher VG and sweetener can shorten the life of a coil, but this seems much shorter than the 1-3 weeks I am seeing online. This may totally be a fluid issue but I have researched and having found my answer. I am going to try 50% VG, unless even less would be optimal, and have it made with no sweetener. I will probably try some other fluids too, this is just so close to my home. That said, could this simply be a fluid problem, or am I doing something wrong? I prime the coil, take some dry hits, and often wait up to 1 hour before using, after I fill the tank. Basically have followed all the typical advice I get. All that does is allow me to up the voltage more quickly without burning the fluid, I really didn't get burn coils before, but I would let them sit in the tank for awhile before I did this process. Lastly, I did not notice any substantial difference from 50% VG to 70%. I also didn't notice any positive results when I reduced the nicotine down from 6 to 3. I am thinking either the juice in general is an issue, or the sweetener. I am going to buy non sweetened juice, probably tomorrow, but it doesn't sound that a coil should only last a day. The coils I can, that look new work find, but they aren't quite as good to start as a brand new one. The fluid burns more quickly, and they they basically are the same. I use rubbing alcohol and a rinse with very hot water, followed by a day or two of drying. Any help would be appreciated, when my mod works, it works great, but only about 6 hours is it really nice. 12 hours is fine, then it gets bad. If something is wrong, I could substantially lower the cost and energy it takes to do this, which is a big perk as someone who has almost entirely quit smoking in a short period of time. Lastly, I use fluid from the same place in lower voltage devices (clearomizers I bought for a 510 battery) with no issue.