When the planting tent begins to push the plant smell out, it becomes a source of trouble. You may use a carbon filter for this, but sometimes it will be saturated and you need to replace the activated carbon or the whole filter itself.
Broadly speaking, the active air carbon filter needs to be replaced after 18-24 months of regular (24 / 7) use. They can last up to four years without high requirements. However, this life depends on carbon quality, usage, humidity, plant type, etc.