Saltwater Aquarium Salinity & Salt Mixing Answers

Q:  What is the proper way to mix salt water?
A:  Always add the salt mix to the water, not the other way around. Adding water to the salt mix briefly creates a highly concentrated solution that can lead to precipitation of some ingredients. 
Always allow newly mixed salt water to circulate with a powerhead or airstone at least overnight before use. This allows the carbon dioxide in the aquarium water to reach equilibrium with the carbon dioxide in the atmosphere, which normalizes pH. It also adds oxygen.
Q:  After dissolving Instant Ocean® in purified water, my calcium and/or magnesium concentration seems lower than expected. Why?
A:  Instant Ocean® is formulated to provide a solution with levels of calcium and magnesium found in natural seawater (NSW), assuming you use purified water to dissolve the sea salt. Tap water most often contains dissolved calcium, magnesium and other minerals that will add to the levels provided by Instant Ocean®. The specific gravity of NSW is typically 1.026 (35 parts per thousand, or ppt, salinity). When dissolved in pure water to a specific gravity of 1.026, Instant Ocean® should provide a solution that has 400 mg/L calcium ion and 1320 mg/L magnesium ion. If Instant Ocean® is dissolved to a lower specific gravity, then these concentrations (and, in fact, the concentration of every other ion) will be proportionately lower.
Q:  My Instant Ocean®/Reef Crystals® will not dissolve properly. I have a cloudy solution with sediment at the bottom of the mixing container. Why?
A:  The most common cause of poor solubility is moisture. Some of the compounds used in sea salts are hygroscopic, meaning they readily and quickly draw moisture from their surroundings. If your sea salt has any “clumps” or hardened sections, then this is a sure sign that moisture has been introduced. Sea salt that has absorbed moisture may dissolve with the addition of aeration. The best way to avoid moisture in your sea salt is to re-seal the container immediately after use.
Q:  Does Instant Ocean® contain a dechlorinator? Does Instant Ocean® contain any ethylenediamine tetraacetic acid (EDTA) or other types of metal chelators?
A:  Instant Ocean® has never contained a dechlorinator or any type of chelator. It is advisable to dechlorinate using a commercially available de-chlorinator when using tap water to dissolve Instant Ocean®.
Q:  What is the difference between Instant Ocean® Sea Salt and Reef Crystals®?
A:  Instant Ocean® is engineered to closely match natural seawater, and Reef Crystals® is enriched to facilitate the growth of corals and other invertebrates in a reef aquarium.