I just wasted the last of my spice trying to figure out what the heck is going on. Last night had multiple breakthroughs, gvg was vaporizing nicely. Now all the sudden I get one hit and it seems the product is gone. I can't figure out if the last of my spice was impure, or if something is wrong with gvg. It was working flawlessly.

Did you try cleaning it?

As Loveall said..

Also, it's easier when having a problem if you describe things more thoroughly so we can access what might be going on. For example, what is on the bottom of your DMT, the GVG screen, did you add multiple screens, or did you do a base layer with plant material or ashes, or did you add a ceramic filter or a volcano liquid pad? Are you measuring the amounts? Did you clean the pipe? How many hits did you take? Do you see any vapor? Is there some condensation on the pipe? Did you try hitting again? did the source of your DMT (which plant it comes from) change? etc