Aquarium water conditioners prepare your tap water for safe aquarium use. Most remove chlorine and heavy metals and stabilize pH. Some condition deionized water. Others create instant natural conditions, such as amazon conditioners and black water conditioners, or cater to specific fish like betta conditioners and cichlid conditioners (many more products like this are available in our vitamins & supplements section).
Use the appropriate aquarium water conditioner when preparing water for aquarium setup or water changes. Most of our stress relief products are great water conditioners too.