NOPOx is a combination of ethanol and vinegar, basically, so you might want to increase the dose of that product. There's also a DIY recipe available. As far as vinegar goes, it'll work the same way as the NOPOx, although it might cause some side effects. Every tank seems to respond differently to carbon dosing.
This article covers vinegar dosing:
http://reefkeeping.com/joomla/index....arine-aquarium
The recommendations are very conservative, though.