Typically, greenish-brown colored stains are related to something organic like algae or leaves that were left on the pool floor. These substances need to be removed as part of the treatment. Organic pool stains are not usually hard to remove but with time, your pool will start to have a dull, light-brown color that you won't be able to remove. The brown discoloration happens very slowly and can be hard to notice at first.  If you have trees that hang over your pool, watch for leaves, branches, or fruit that may drop down into the water. You can use a pool skimmer to routinely clean out the debris. Any organic debris that floats to the bottom of your pool needs to be removed with a pool vacuum. You can use a hand-held vacuum or an automatic pool vacuum that uses a sensor. If permanent stains do develop, you can drain your pool water and acid wash your pool if it has a plaster liner. This is not something that you can practice all of the time, as it involves a purposeful stripping of a thin layer of pool plaster. In order to restore the bright white surface, you need to use an acid wash around every five years. This may quickly remove greenish-brown colored stains that build up from organic stains. You may also want to try an enzyme based pool chemical. All natural pool enzymes will eat away at organic material to remove the pool stain with little or no scrubbing and without the use of harsh chemicals that damage pool liners. If your stain is all around the waterline of the pool because of material floating at the top, an enzyme-based cleaner will help to break down organic compounds and oils by speeding up the chemical reactions that assist in making stains virtually disappear on their own. Follow up with a thorough brushing to make sure you've got all the left behind debris and oil. Organic stains are best addressed by heavily chlorinating the water, then giving your pool a little TLC with a good brushing. You can use a long handled stiff brush to get all around your pool. Try pouring a small amount of...

How would you rephrase that briefly using Vietnamese?
Loại bỏ vật chất hữu cơ khỏi mặt nước. Rửa hồ bơi bằng axit. Sử dụng phương pháp gây sốc enzym và bàn chải lông cứng để loại bỏ vết bẩn. Gây sốc cho hồ bằng clo. Loại bỏ vết bẩn cục bộ bằng cách chà rửa với axit muriatic. Chà mạnh tay để thay cho việc dùng hóa chất mạnh.