Contains important strontium
Along with the macro elements magnesium and calcium, strontium is an important component of corals and other invertebrates and needs to be supplied regularly.
Use the cap as a measure.
Add once weekly one capful sera marin 5 for every 100 liters (26.4 US gal.) of aquarium water. sera marin 5 was developed along with sera marin 1 and 2. Strontium and Calcium are required in a certain ratio.