The proper pH for a betta (also called a Siamese fighting fish) is somewhere between 6.8 and 7.2; however, maintaining a constant pH is more important that having the “proper” pH. Betta can adapt to different pH levels, provided the changes are gradual. This is most especially important when changing the tank water.
Maintaining a Steady pH Level
Having pH levels between between 6.8 and 7 is preferable, but those between 6 and 8 should not cause harm to your betta. The most important point about pH is to remember that the level is not as important as the constancy. Bettas can adapt to different pH levels, provided those levels change gradually. This makes water changes and cleanings especially important because whatever the pH level is for the water your fish lives in, it needs the level to stay that way. Before changing the water, you will need to measure the current pH level, and then adjust the new water to match that level. This adjustment must be done before putting the fish into the new water, otherwise you risk shocking the fish’s system. Performing frequent partial water changes and vacuuming the gravel are effective ways to keep water pH stable.
Adjusting pH Levels
The easiest way to adjust levels is to buy a test kit which contains chemicals referred to as “pH up” and “pH down.” Many common kits contain these chemicals, which you add to your tank water to raise or lower the pH level. Some people recommend adding a piece of wood to your tank to lower the pH or adding a seashell or a coral skeleton to raise the pH as easier, “softer” methods of adjusting pH levels; be aware that these methods will take longer to produce noticeable effects. To lower pH, add an acid to the tank water; add a base to increase pH. However, regulating pH in this way becomes more difficult if your water contains buffers, and a betta buffer is recommended to keep the pH levels constant. A buffer will make water changes more difficult, because the new tank water must match the pH levels of the old, existing tank water, and this will require a careful mix of buffers and pH adjusters.
Testing pH Levels
Use a tank testing kit. These are available from any aquarium supply store, and usually include guides for proper use and testing. Take a sample of your tank’s water from about 8 to 12 inches below the water line.