Description
Combined magnesium chloride and sodium bicarbonate dosing
General procedure
This method supplies magnesium and carbonate hardness by adding hw® Magnesium Chloride Hexahydrate (MgCl₂ · 6H₂O) and hw® Sodium Bicarbonate (NaHCO₃). Sodium and chloride remain as additional sodium chloride (NaCl), which can gradually alter the seawater composition.
The sodium-chloride-free salt mix hw® MineralMarin supplies the other marine salt components. Salinity also rises gradually with this method. Monitor it regularly, taking temperature into account when using a hydrometer, and compensate for the increase during water changes.
Combined magnesium sulfate and magnesium chloride dosing
The principle
Magnesium is an important component of natural seawater and is consumed by biological processes in the aquarium. Adjust the magnesium level as needed to prevent a deficiency. The reference range given here for natural seawater is 1250–1380 mg/l, with seasonal and geographical variation.
Use hw® Magnesium Chloride Hexahydrate together with a precisely measured amount of hw® Magnesium Sulfate Heptahydrate to avoid an unfavourable change in the chloride-to-sulfate ratio.
General procedure
The quantities account for molar masses, water of crystallisation and the chloride-to-sulfate ratio. Use the following combination to supply 1.00 g of magnesium:
- 0.95 g hw® Magnesium Sulfate Heptahydrate (MgSO₄ · 7H₂O)
- 7.58 g hw® Magnesium Chloride Hexahydrate (MgCl₂ · 6H₂O)
Example
A marine aquarium containing 500 l of water has a magnesium level of 1200 mg/l. Raising it to 1300 mg/l requires an additional 100 mg/l × 500 l = 50 g of magnesium.
- 50 g × 0.95 = 47.50 g hw® Magnesium Sulfate Heptahydrate
- 50 g × 7.58 = 379.00 g hw® Magnesium Chloride Hexahydrate
Dissolve both salts together in 600 ml of reverse osmosis water, then make up to 1000 ml. Add 100 ml per day over the next 10 days. Check the aquarium magnesium level on day 5 and adjust if necessary.
