Blue Treasure Reef Sea Salt Mix for Marine Aquarium 6.7 kg Trusted seller since 2007 Approximately 6.7 kg good for up to about 50 gallons Maximum 3 pieces 6.7 kg bags per order number please . Also do not order other item(s) together with this salt mix order. So items are safe in shipping and we can pack it properly. This reef salt is suitable for both reef tanks with LPS corals and fowlr (fish-only with live rock). For SPS corals please order the SPS version. You can normally use lower specific gravity/salinity for fish only salt water aquariums. Higher salinity is recommended for marine tanks with invertebrates such as corals. For best results use a accurate hydrometer or refractometer. Consume entire bag once opened. If you really must store consume opened bag as soon as possible. Just seal the zip lock well after using so moisture will not enter the bag. From manufacturer's description: LPS Reef Sea Salt 6.7kg/bag The new formulas of Blue Treasure synthetic series sea salts are the result of years of research into the physiological demands of corals in the reef aquarium environment. The raw materials of all series Blue Treasure synthetic sea salts are selected from pure, food grade ingredients and contains all kinds of trace elements, in accordance with the composition of seawater near coral reefs, as well as some other special vitamins and protective colloids. The Blue Treasure sea salt for coral reef aquarium contains all trace elements found in natural coral reef seawater, such as calcium(Ca), magnesium(Mg), iodine(I), strontium(Sr), molybdenum(Mo), iron(Fe), rubidium(Rb), manganese(Mn), barium(Ba), selenium(Se), fluoride(F), bromine(Br), lithium(Li), zinc(Zn), aluminum(Al), nickel(Ni), cesium(Cs), cobalt(Co), boron(B), Vanadium(V) and water-soluble B1, B12,etc.. It does not contain any harmful elements and nutritive elements, such as nitrate(NO3), phosphate(PO4), and silicate(Si), etc.. The Blue Treasure sea salts are used for many years in public aquariums, zoos, and scientific institutions around the world. If you have question(s) about the product please message us before ordering. Please be sure of your order as item cannot be returned or exchanged due to mistake in order, change of mind, etc.