I have 2, 6 gallon carboys, one apple & the other peach. The apple is bubbling really good, the peach not at all from what I have seen. Can/should I add more yeast or sugar to kick start it?
When you say bubble are you meaning the airlock? It could be an issue with the seal of the carboy. Sometimes there is a leak in the seal so the brew is "bubbling" (this happens with the CO2 escaping when the alcohol is being produced) but you just cant see it in the airlock. As the others say we will need more information to solve the issue for you but you can always try the brew and see if you can taste alcohol or just off fruit.