This is really exceedingly difficult to answer with the amount of information you have provided. I can try and give some advice, but I have no idea what device you want to put this tank on or what your battery can handle safely. I'm not even 100% sure which tank you're using now.
I THINK you're using a Nautilus Mini, which truthfully is still one of the best non-sub-ohm tanks out there, IMO. If your device is not capable of subohming, then you might want to check out something like the Eleaf GS-Air M/MS or a Kanger Aerotank, but truthfully I would probably recommend the Nautilus Mini over either of those. There are some other options, but as far as I know those three are among the most popular in the category. Someone else might know better as I don't regularly use any of them anymore. Sometimes my GS-Air.
If your device is capable of subohming, then you have more options. If you're not sure if your device is capable of firing coils below 1 ohm, it can usually be found online. Typically-- if not always-- these devices can put out at least 30W. Many regulated devices that hit the market longer than a year or so ago are NOT capable of subohming. Some may be that I'm not thinking about, but no eGos, no original iSticks or MVP 20Ws, no Provari 1 or 2s or 2.5s without upgraded internals, no Lavatubes <2.5 etc.
I really can't stress enough that you should not subohm unless you're certain your battery is capable of it, but I also feel like in August 2015 I would be remiss not to mention subohm tanks. If you like Aspire, the Atlantis and Triton tanks are reliably popular and brand-spankin' new, respectively. I enjoy Kanger Subtanks. The Arctic, Herakles, and Innokin i-Sub (G) come to mind. There are so many others and what is "best" is so subjective.
Some "subohm tank"s also have coil options that are above 1Ω.
Lastly, if you are comfortable rebuilding, you could use almost any RTA or tank with stock coils and an RDA deck both, like Kayfun Lites in the former category or the Aspire Triton or Kanger Subtank Plus and Mini in the latter. Just for example.
Here's my advice, in a nutshell: If your device is not capable of subohming and you're bored with (what I assume is) your Nautilus Mini, get an eLeaf GS-Air M or MS ("Mega" or "Mega Shorty") for $10 and see how you like it. It's super cheap, pretty good, and the coils are decent and can handle pretty high VG juice. If you're thinking about a subohm tank, feel free to start with any of my suggestions and do more research. You have to decide what you want from your tank (great flavor, good clouds, etc.) and asking in the Ask the Vets forum doesn't allow you to respond with answers to all these questions. Without more information, that's about what I can tell you. Watch some Youtube videos and figure out which tank looks like it will fit your style and device. You can always ask more specific questions about a particular tank in other forums on ECF, where you can have an actual dialogue.
Yeah, that's what I've got.
TLDR: I don't know what battery or tank you're using now. Consider trying out an inexpensive eLeaf GS-Air M or MS. If your battery can subohm, do some more research and ask questions in a forum in which you can reply before deciding.
A requisite note on subohm vaping: It is imperative that you are certain your device is capable of handling coils with resistances of less than 1Ω. Subohm vaping comes with inherent risks and vapers should use extra caution when considering going that route. Fortunately, most regulated devices will simply not fire if you try to use a coil below the set minimum resistance, but this isn't necessarily true across the board and it remains important to be aware of your battery's limitations. One should never use sub-1Ω coils on a(n unregulated) mechanical mod without advanced knowledge of ohm's law, battery safety, and amperage limits (etc.). Nothing in this post is meant to endorse risky vaping behaviors.
