There is no standard dosage; the appropriate amount depends on your personal preference, the size of the room, and the sensitivity of those present. A common and cautious approach is to start with a small amount, such as 1-2 tablespoons (15-30 ml) mixed with water in your ladle, and pour it onto the hot stones or the sauna stove to create the initial aromatic steam. You can then observe how the scent develops and adjust slightly for the next round of steam generation. In a bathtub, a similar small amount added to the hot water is usually sufficient, as the warmth of the bath will gradually release the aroma.
The scent will naturally fade over time as the aromatic compounds evaporate. Reapplication is possible during a long sauna session if the atmosphere becomes neutral again, but constant reapplication is not advisable, as it can lead to an overly saturated, heavy atmosphere that is difficult to clear. It's more effective to create a fresh aromatic wave at the start of each new round of steam. Between sessions, ensure proper ventilation to allow the scent to dissipate fully before introducing a new aroma.