For salt (heavy weight), you must select a separate shipping cost of €15, no shipping costs. Description Tropic Marin Pro Reef, Pharmaceutical Grade Sea Salt Features: Tropic Marin PRO-REEF sea salt is designed for the special care conditions required for a reef aquarium: the optimized concentrations of calcium and magnesium promote coral growth. The adapted buffering capacity stabilizes the pH value and carbonate hardness, even when using calcium reactors and other calcium supply methods. Thanks to the precise coordination of all influencing factors, natural and long-lasting living conditions are created in the aquarium with an alkalinity of 7-8 °dH. Tropic Marin PRO-REEF creates the ideal environment for keeping fish, corals and other invertebrates in modern reef aquariums. Tropic Marin PRO-REEF contains all the main and trace elements of tropical seawater in a natural ratio. Main elements: Calcium; Chlorine; Magnesium; Potassium; Sodium; Sulfur. Trace elements: Aluminum; Antimony; Arsenic; Barium; Beryllium; Bismuth; Boron; Bromine; Cadmium; Cesium; Carbon; Cerium; Chromium; Cobalt; Copper; Dysprosium; Erbium; Europium; Fluorine; Gadolinium; Gallium; Germanium; Gold; Hafnium; Holmium; Indium; Iodine; iridium; iron; lanthanum; lead; lithium; lutetium; manganese; mercury; molybdenum; neodymium; nickel; niobium; nitrogen; osmium; palladium; platinum; praseodymium; rhenium; rhodium; rubidium; ruthenium; samarium; scandium; selenium; silicon; silver; strontium; tantalum; tellurium; terbium; thallium; thorium; thulium; tin; titanium; tungsten; vanadium; ytterbium; yttrium; zinc; zirconium. Dosage: To achieve a salinity of 32-35 ‰ (psu), dissolve 35 ml (approximately 37-40 g) of PRO-REEF per liter of water in a container, circulating the water constantly. Seawater prepared in this way can be used as soon as the salt is completely dissolved and the solution is clear. The relative density of the sea salt solution should be 1.025 - 1.027 at a temperature of 25°C / 77°F. Once a new aquarium is set up, it takes a few weeks, through water filtration and appropriate lighting, to create stable biological conditions for the care of sensitive marine organisms. A partial weekly water change of up to 10% with Tropic Marin PRO-REEF helps maintain optimal water quality, in which your "pupils" will thrive.