A tank size of 2.5 gallons (9.5 liters) at minimum is recommended for a single betta fish. If you have more than one fish, you should get a bigger tank to accommodate all of the fish. If you have a larger tank, you may not need to change the water as frequently. Toxins will build up more quickly and in higher concentration in a smaller tank. Having a good pH balance will help restrict the levels of ammonia, nitrite, and nitrate, which will in turn keep your betta healthy. An ideal pH is 7.  Treat the water with a dechlorinator. Follow the manufacturer’s instructions to put this into the water. Test your water for ammonia using a test kit. You will either use a dip-stick test or gather a water sample to test the water. Your ammonia level should read 0, since you just used a dechlorinator. Measure the ammonia level once per day until you start seeing ammonia levels. This will tell you how long you can go before changing the tank’s water. Twice a week, you should change the water in the tank to make sure that you don’t have dangerous levels of ammonia, nitrate and nitrite building up. You can use distilled, bottled or tap water, but each kind of water needs to be treated before it goes in the tank in order to restore the proper balance of nutrients in the water.  Change 25%-50% of the water in the tank twice a week. This means you add 25% new water and keep 75% of the old water (or 50% new and 50% old). Use aquatic water conditioners, available at your pet store for $5-$10, to adjust pH levels in the water. Use them according to the manufacturer’s instructions. Add 1 tablespoon of aquarium salt and 1 drop per gallon of a fungus preventative like Aquarisol. Do not use table salt in place of aquarium salt. Table salt may have additives like iodine and calcium silicate, which can be harmful to fish. Cycling your tank means that you build up good bacteria in the tank so that your fish can flourish. This bacteria will help keep ammonia levels low by breaking down fish waste into nitrite and then into nitrate. Start...

How would you rephrase that briefly using Vietnamese?
Mua bể cá lớn hơn. Thử nước trong bể. Thay nước và xử lý nước. Tạo chu trình ni tơ trong bể cá. Điều hòa nhiệt độ nước. Dùng máy lọc nước trong bể cá. Pha muối aquarium vào nước.