Carbon Dioxide Tablets are tablets which are added into the water. These Tablets claim release to carbondioxide slowly in the water. They are used in planted aquariums where the plants need carbondioxide to grow.
However, skeptical aquarists say that these tablets release the carbondioxide too fast to be of any use. They may have a marginal effect in small aquarium. Big Planted aquariums need other methods of Carbondioxide addition.
If you are going to try the tablets. Keep the following things in mind.
However, the dosage should be carefully followed. The dosage is generally mentioned in the cover. Eg. 1 tablet or 2 tablet per 50 litres.
The level or carbon dioxide affects the pH of the water. Any drastic change in the pH can be fatal to the fish.
At night plants give out large quantities or carbon dioxide. This can affect the fish. Hence, it is better to start at small doses and then go the recommended dose.
If you find fish gasping for air in the surface in the morning, stop using the tablets.