which one is good when you have low magnesium Magnesium Chloride /Magnesium Sulfate and where is the difference???
You should be using both at a ratio, which is dependent on how you sup the tank. The article Doni posted show you why. Here are the reason for that.
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com
Recipe #1 is for use in reef aquaria whose pH is normal to low. In practice, more reef aquarists end up choosing this recipe than Recipe #2. It will tend to raise pH due to its alkalinity part's elevated pH, as do most of the commercial two-part additives. The increase in pH depends on the aquarium's alkalinity and, of course, on how much is added. Adding on the order of 0.5 meq/L of alkalinity increases the pH by about 0.3 pH units immediately upon its addition (and even higher, locally, before it has a chance to mix throughout the aquarium).
If you are using limewater (kalkwasser) and the aquarium is at pH 8.4 or above, this recipe is not the best choice. Otherwise, it is likely to be a good option. It is twice as concentrated as Recipe #2, because the baking process makes the baking soda more soluble.
Recipe #2 is for use in reef aquaria whose pH is on the high side (above 8.3 or so). It will have a very small pH lowering effect when initially added. The pH drop achieved will depend on the aquarium's alkalinity and, of course, on how much is added. Adding on the order of 0.5 meq/L of alkalinity drops the pH by about 0.04 pH units immediately upon its addition.
If you are using limewater (kalkwasser) and the aquarium is at pH 8.4 or above, this recipe may be the best choice. It is half as concentrated as Recipe #1 because the raw baking soda is less soluble because it's unbaked.
Recipe #1, Part 3: The Magnesium Portion
The magnesium portion 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 #1, Part 3A
Dissolve Epsom salts (3 cups) and magnesium chloride hexahydrate sold by the Dead Sea Works company (5 cups) in enough purified freshwater to make 1 gallon 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 a gallon of both parts of Recipe #1, add 610 mL (2 ½ cups) 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 47,000 ppm magnesium, 70,000 ppm sulfate and 86,000 ppm chloride.
Recipe #1, Part 3B
Dissolve a 64-ounce container of Epsom salts (about 8 cups) in enough purified freshwater to make 1 gallon total volume. This solution is added much less frequently than the other two parts. Each time you finish adding a gallon of both parts of Recipe #1, add 610 mL (2 ½ cups) of this stock solution. It can be added 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 47,000 ppm magnesium and 187,000 ppm sulfate.
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 (3 cups) and magnesium chloride hexahydrate (5 cups) in enough purified freshwater to make 1 gallon 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 a gallon of both parts of Recipe #2, add 305 mL (1 ¼ cups) 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 47,000 ppm magnesium, 70,000 ppm sulfate and 86,000 ppm chloride.
Recipe #2, Part 3B
Dissolve a 64-ounce container of Epsom salts (about 8 cups) in enough purified fresh water to make 1 gallon total volume. This solution is added much less frequently than the other two parts. Each time you finish adding a gallon of both parts of Recipe #2, add 305 mL (1 ¼ cups) 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 47,000 ppm magnesium and 187,000 ppm sulfate.
