For determining the alkalinity (KH)

The carbonate hardness (KH) or alkalinity of a water sample characterises the buffering capacity, i.e. the ability to maintain the pH value of the water. There are many terms in water chemistry to describe the buffering capacity with varying definitions. The term “carbonate hardness” is customary in fishkeeping; however, it is the alkalinity which is measured. In this test, both terms are used synonymously. The reading for alkalinity is usually given in degrees of German hardness (°dH).

The alkalinity should be tested in all aquariums with great regularity. If the alkalinity in the aquarium is too low, the pH value can sink (sudden drop in acidity) to a level which is life-threatening for many fish and invertebrates. In reef aquariums, an adequate alkalinity level is essential for strong coral growth. On the other hand, an overly high alkalinity in saltwater tanks can lead to calcium carbonate precipitates and also have a negative impact on coral growth. The alkalinity in saltwater aquariums should range from 6 to 9 °dH. The alkalinity in freshwater aquariums should not fall below 3 °dH.

The Tropic Marin KH-Test kit makes it possible to quickly determine the alkalinity of your aquarium water by ease of use and high accuracy.

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.