- 1). Test your aquarium water by following the directions on the pH test kit. On a scale from zero to 14, a pH of seven is considered neutral. Water showing a pH of greater than seven is considered alkaline.
- 2). Dissolve 1 teaspoon of baking soda in a glass of water for each 10 gallons in the tank. Add it to the aquarium and wait 24 hours. As an alternative to the baking soda method, use a commercially available product from a pet store. If the rise in alkalinity is too extreme, it can kill the fish in the tank. Conduct a partial water change to bring the pH into range.
- 3). Siphon no more than 20 percent of the total water volume from the tank. Replace it with tap water and wait 24 hours before testing the water again. Partial water-changes are an effective means of raising alkalinity slowly in tanks where the pH is between six and seven.
- 4). Add crushed coral or seashells to the gravel. While every tank responds differently to the addition of substrate, you can use 2 pounds of seashells for every ten gallons of water as a starting point. Crushed coral or seashells are a source of calcium and magnesium, essential minerals that produce a level of hardness and buffering capacity to the water. It is the buffering capacity that keeps the pH stable in an aquarium. During a pH crash, the buffering capability of the existing substrate is used up, and new material is needed to raise alkalinity.
- 5). Test the water again with your pH test kit. As the alkalinity is restored to healthy levels in the tank, you will notice a favorable change in the behavior, physical condition and breeding habits of your fish.
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