Features:

For high precision determination of the Ca and Mg concentration in saltwater

Along with sodium, potassium, chloride and sulphate, calcium (Ca₂⁺) and magnesium (Mg₂⁺) are two key components of natural seawater. Magnesium and, above all, calcium are important growth factors for organisms which form calcareous skeletons, such as hard coral and coralline algae – both elements form the basic substance of the calcareous skeleton. Furthermore, magnesium and calcium are involved in numerous biochemical processes. In saltwater applications, the reduction in the magnesium or calcium concentration caused partly by cellular metabolism and partly by skeleton formation means it is necessary to test the concentration levels on a regular basis and, if required, add more of one or both ions. This makes it possible to guarantee optimum, near-natural living conditions for all organisms and to prevent long-term damage.

In natural seawater, the calcium concentration is 400-410 mg/l (ppm) and the magnesium concentration is 1280-1320 mg/l (ppm). They also have a fixed ratio of 1:3.25 to one another. Due to the chemical and biochemical interdependencies between calcium and magnesium, you should also aim to achieve this concentration ratio in saltwater tanks.

With the high resolution titration test Tropic Marin^® Calcium/Magnesium Combitest Professional the calcium and magnesium concentrations can be determined reliably and separately with a resolution of 4 mg/l Ca and 20 mg/l Mg.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months’ remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number — or email us, if you would rather — and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.