Flux is a dangerous essence that is released when extra aspects are not used in the crucible. It is released into the Aura and picked up by Aura Nodes. The higher the Flux level, the lower the Vis level, the more dangerous the chunk. When the Flux is at dangerous levels, it can start spawning wisps and explosions, but everytime it does, the Flux level drops. There is two ways to stop creating Flux. Use exact amount of Aspects necessary, or use an Arcane Alembic.