Contains the important trace element iodine.

Iodine does not remain stable for a long time in an aquarium. It is quickly converted into iodide, turning it ineffective for many plants and animals. A constant iodine level is achieved by daily addition of Sera Marin 7. Varying concentrations and deficiencies are avoided.
Sera Marin 7 in the dropper bottle allows daily addition without annoying measuring.