One thing that our customers like about our CD Max is the windows on the side of the e-tank which allows you to see how much liquid is left.
1. When looking at the windows on a full ClearDraw Max, you will notice some coloration of the cotton itself. The actual color, as well as the depth of that color, may vary from flavor to flavor. For example the Mango Tango will have an orange tint and a lesser amount of color depth while the Atlantic Cut will be significantly darker and have a greater amount of depth to the color.
2. As you use the e-tank you will notice the color fade slowly from the cotton in the chamber. The less color you see the closer the CD Max is to depletion.
(New vs Empty Cartridge)
While you may continue to get some vapor from a depleted e-tank (you will certainly notice a drop in the amount of vapor produced) it is prudent to cease using the cartridge at that point. If you continue to puff then you may taste an off, slightly burnt flavor which means that the cotton itself is starting to burn a bit as there is no liquid in the chamber.