Provide your pet balanced water, making it as close as possible to that in which they live in nature. Information on the required pH they can get in specialized shops or in the directories. Measure the water pH tester or other device.
Water filter for aquarium peat filter. This filter saturates the water humic acids that reduce pH to a neutral point (7,0). Peat reduces the carbonate hardness of the water and does not breed bacteria that will hurt the fish. Don't forget to change the filter – it would wash off over time.
Put in the water a snag. Snag will act not only as a decorative element – it also contributes to a decrease in the pH of the water, however slightly, the but sometimes it to the desired level. Of course, not every snag will be appropriate, and it requires a thermal pre-treatment of salt water and a long soaking. However, the snag can be essential for some species of fish.
Enter the carbon dioxide CO2 into the aquarium. For this purpose use special spray gas, certain devices, or even the bottle of yeast. This will not only lower the pH to the desired fish, oxidizing water, but also will accelerate the growth of aquatic plants.
Use acid buffer. A buffer can be considered a primer of special granules, available in the market. Provide buffering bicarbonate ions (bicarbonate) and carbonate ions of a carbonate salt). Insufficiently buffered water is more subject to rapid changes in pH, in contrast to the well-buffered.
Replacing part of the water more than soft water (boiled or acidified phosphoric acid) or water treated with reverse osmosis (purified). The addition of water, pH should be below about 7.0, it is necessary to produce small portions to avoid abrupt changes in acid-base balance. You need to constantly follow the changes of the pH level to be aware of the fact that your aquarium is happening and to react.