How do you raise the pH of a fish tank?

1. Add baking soda (sodium bicarbonate) - Baking soda is a common and inexpensive way to raise the pH of your aquarium water. For every 10 gallons of water, add one tablespoon of baking soda. Dissolve the baking soda in a small amount of water before adding it to the aquarium to avoid disturbing the gravel.

2. Add crushed coral or limestone - Crushed coral or limestone can be added to the aquarium filter or substrate. These materials will slowly dissolve and raise the pH of the water.

3. Use a commercial pH buffer - There are a number of commercial pH buffers available that can be added to the aquarium water to raise the pH. Follow the directions on the product label carefully.

4. Aerate the water - Aeration can help to increase the pH of the water by releasing carbon dioxide gas. This gas can lower the pH of the water, so increasing aeration can help to counteract this effect.

5. Reduce the amount of acidic water in the tank - If you are using a reverse osmosis (RO) or deionized water filtration system, this can lower the pH of the water. You can reduce the amount of acidic water in the tank by blending it with tap water or by using a remineralizing agent.

It is important to note that raising the pH of the aquarium water too quickly can be harmful to the fish. Always make changes to the pH gradually over a period of several days.