it gves a good idea of where to start. their calculations arent PERFECT,but once u see how easy itis to rebuild those coils, u will figure it out really quick . i have thw nano and the mini, i havent bought a coil yet for either. ve been rebuilding them since the first one was burnt. i also have the atlantis, persnally i wish that i hadnt got it cuz rebuilding those is a bitch, so the40$ tank just sits there .stick with the 28 or 26. 30 and 32 will have u aggrivated