Tạo thói quen bảo dưỡng hồ bơi. Ngăn ngừa vết bẩn kim loại quay lại. Không để rác hữu cơ xâm nhập vào hồ để ngăn chặn vết bẩn hữu cơ xuất hiện.

Given the above summary, write a detailed text in English for it.
Prevention is much easier to maintain than stain removal and cures. Have a sample of your pool water tested for ideal chemical balances either by a professional or with an at home kit every week. If you fill your pool from a source other than "city water" you should also test the fill water because well water carries a lot of iron that can leave behind stains.  Do small shock treatments every week to prevent algae outbreaks. Scrub the bottom of your pool several times a week as a preventative measure. Make sure to regularly test your water for metals, as the stains will keep coming back if you have a highly metallic pool. Remember, metals are naturally occurring and can be added to your swimming pool with fill water, or they may be introduced into the pool water through corrosion of your pool equipment or plumbing. It is important to monitor metal levels every week.  Use a sequestering agents, also known as Chelators. They tie-up minerals in a solution which prevent them from floating free in the water causing stains.  Just make sure they do not have phosphonic acids, as they break down into phosphates and can cause an algae outbreak. Disposable absorbent bags also remove and eliminate metals. Just drop one into your skimmer basket (or pump basket) and it will absorb metals such as copper, iron, manganese, cobalt, silver, and nickel. Either skim your pool or use an automatic pool vacuum to clear out leaves, berries and branches that fall in. You should also invest in a durable winter pool cover that you can use when you are not using your pool. Dark pool staining can occur from mudslides or mulch-slides into the pool. If you can't prevent these materials from going into your pool, try re-coating your pool with a dark colored plaster or liner to help hide these types of pool stains.