Recipe #2
In this recipe three stock solutions are created. Two are used frequently, and one is used only occasionally to balance other elements not added in the first two. The solutions can be mixed and stored in any plastic or glass container.
Recipe #2, Part 1: The Calcium Part
Dissolve 200 grams (about 1 cup) of calcium chloride dihydrate (Damprid) in enough water to make 3 litres of total volume. You can dissolve it in about 1 litre of water, and then pour that into the 3 litre container and fill it to the top with more freshwater. This solution is about 14,700 ppm in calcium.
Note that the solution will get quite warm when dissolving the calcium chloride.
Recipe #2, Part 2: The Alkalinity Part
Dissolve 235 grams of baking soda (about 0.9 cups) in enough water to make 3 litres total. This dissolution may require a fair amount of mixing. Warming it speeds dissolution. This solution will contain about 750 meq/L of alkalinity (2,100 dKH). Be sure to NOT use baking powder. Baking powder is a different material that often has phosphate as a main ingredient.
Once these two solutions are created, they can be added as frequently as necessary to maintain calcium and alkalinity. For further dosing instructions, see below.
Recipe #2, Part 3: The Magnesium Portion
The magnesium portion again gives us two options, with Part 3A being preferred from an aquarium chemistry standpoint. Pick one and follow the same dosing directions regardless of which version you select.
Recipe #2, Part 3A
Dissolve Epsom salts (2.4 cups) and magnesium chloride hexahydrate (4 cups) in enough purified freshwater to make 3 litres total volume. There will likely be a precipitate that forms even if you fully dissolve both ingredients separately. That precipitate is calcium sulfate (calcium as an impurity in the magnesium chloride and sulfate from the Epsom salts). It is fine and appropriate to dose the precipitate along with the remainder of the fluid by shaking it up before dosing.
This solution is added much less frequently than the other two parts. Each time you finish adding 3 litres of both parts of Recipe #2, add 242 mL (1 cup) of this stock solution. You can add it all at once or over time as you choose, depending on the aquarium's size and set up. Add it to a high flow area, preferably a sump. In a very small aquarium, or one without a sump, I suggest adding it slowly.
The first time it's added, I recommend adding just a small portion and making sure there isn't any problem (such as corals closing up due to stress) before adding the remainder. Make sure corals and other organisms don't get blasted with locally high concentrations of the main ingredients or impurities, or else they may become stressed. This solution contains about 37,300 ppm magnesium, 55,500 ppm sulfate and 68,000 ppm chloride.