When it comes to adjusting the ph value, we must first understand the influence of the things in our fish tank on the pH value. At present, the commonly used filter materials seem to have no effect on lowering pH value. The only thing that didn't raise the pH value in the water was volcanic rock (just didn't raise it), and the rest, whether it was all kinds of cotton, mushroom house, glass ring, ceramic ring, medical stone and coral stone, were presented when entering the pool. The pH value of tap water varies from place to place, but as we all know, water beneficial to human health is weakly alkaline, so basically, the pH value of tap water will be between 7.2 and 8.8 regardless of north and south. ▌ Effective method of adjusting pH value Remember one sentence: It is easy to increase, but difficult to decrease. The treatment of filter materials (pre-adjustment of pH value) is the most important. Through the pretreatment of filter material, the trouble and risk of adjusting pH value in the later stage can be reduced. Methods: Wash the filter material to be replaced 5-7 days in advance, then put it into a basin or other container, add water and pH lowering agent, soak the filter material in water with ultra-low pH value to neutralize the alkalinity of the filter material, add nitrifying bacteria after 24-48 hours, and culture the bacteria synchronously. After soaking, replace the filter media in batches to prevent the nitrification system in the pool from being damaged. Note: Because the release of alkaline substances from the new filter material is a continuous process, the pH value of water in the filter material is often tested during soaking. If it exceeds the target value, a pH reducing agent should be added to neutralize alkaline substances, and the filter material should be tested again the day before entering the cylinder, so that the pH value will not exceed the target value. In addition, it is suggested that the special filter materials for bacteria culture such as cotton, glass ring and bacteria room should be replaced every 4-6 months, and the functional filter materials such as medical stone, volcanic stone and coral sand should be taken out and cleaned every 3-4 months, and cotton should be cleaned every two months at most. Dirt deposition and filter material aging are the main causes of water turbidity and diseases in the pool, especially bacterial infections. Selection of filter media Knowing the influence of filter media on pH value is related to how to choose filter media. Needless to say, cotton, mushroom house or 1 is essential. Volcanic rock: it has little effect on pH value and can be used. Medical stone: It can improve the pH value to a certain extent, but it is said that medical stone will release some trace elements in water, so it is recommended to use it in a small amount. Coral sand: Coral sand will release all kinds of alkaline substances in water, and it will be released continuously, and will not stop because of the length of use or immersion in low pH water. Therefore, it is recommended to use less. Elemene leaves: Elemene leaves have no effect on lowering pH value, and slag will be produced after a few days. It is not recommended to use them. It's simple: change the water, change the filter material and add coral sand. The effective way to reduce pH value is to treat it in the early stage of filter material replacement (see above for the method). Add black water (good effect, natural, the disadvantage is very black water). Adding pH lowering agent (personally recommend Dulux brand), the effect is good, not black water. Usage and precautions of pH regulator: The value of pH regulator can reach 1-2, so it has a strong regulating effect on water body. If it is added too much, it will easily cause water quality oscillation. So I suggest you use it like this: 1. Use it in a closed water tank. According to the instructions, after the trapped water tank is filled with water, add it, adjust it to the required value, and then get trapped, which is very large. 2. Use it directly in the cylinder, use it in strict accordance with the instructions, and then add it several times. Never pour too much at a time. Be sure to use a small amount and add it several times. 3. Soak the filter material (see above). The pH reducer must not be put too much at a time, and it is better to put it in a small amount for many times. If you accidentally pour too much water, don't change a lot of water immediately, but change a little water. Add coral sand to adjust (remember to take it out after adjustment), and changing water in large quantities will do more harm to fish and have higher risks.