DUO is designed in a way that all essential components of the seawater are added so no ionic shift should happen.
Due to the dosage of DUO, additional sea salt is produced, which increases the salinity. This should be taken into account for water changes.
When dosing 1 liter of DUO, ~ 8.7 liters of seawater should be replaced with osmosis water to keep salinity constant.
Example 1) In a 1000 liter tank, 100 ml DUO are dosed daily. In order to keep salinity constant, once a week 6 liters of water should be replaced by osmosis water
Example 2) In a 100 liter tank, 10 ml DUO are dosed daily. To keep the salinity constant, 0.6 l of water should be replaced once a week with osmosis water.