pH is the measure of acidity of water, on a scale ranging from 0 to 14. A pH of 0 is the most acidic, while a pH of 14 is the most alkaline. Water with a pH of 7.0 is considered "neutral". Different geographies have different tap water conditions with different pH levels, while fish require a specific pH level to thrive. API PROPER pH 7.5 Freshwater Aquarium pH Stabilizer automatically sets and stabilizes the pH level in freshwater aquariums to 7.5 which is perfect for Goldfish, Guppies, Barbs, Swordtails, Platies and Mollies. API PROPER pH 7.5 Freshwater Aquarium pH Stabilizer also removes toxic compounds from tap water such as chlorine, neutralizes chloramines, detoxifies heavy metals, and adds electrolytes, making tap water safe for fish. Use this aquarium treatment when setting up a new aquarium, adjusting pH, or changing water. pH in an aquarium can fluctuate due to fish waste, uneaten food and addition of tap water. It is recommended to test water for pH weekly. With API aquarium products, it's easy to keep a beautiful saltwater, freshwater or reef aquarium. For almost 60 years API has developed premium solutions with proven and effective results for your family and ours. API offers a range of testing kits, water conditioners, and nutritionally superior food, because we're dedicated to making a better underwater world. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. At API, we understand the rewards and relaxation of fishkeeping because we have a passion for fish too. DIRECTIONS Use when setting up a new aquarium, adjusting pH in an established aquarium and changing water. Shake well to mix powder. Add 2 teaspoons for every 10 U.S. gallons (38 L) of aquarium water. Repeat dose when pH test indicates a pH change of more than .2. Not for use in aquariums containing live plants. Tips: To keep aquarium fish healthy and colorful, it is necessary to maintain a stable pH in the proper range. Goldfish live-bearing species thrive at pH 7.5. When using PROPER pH with water clarifiers or in hard water, a temporary cloud may form. This will not harm fish and will quickly be filtered out of the aquarium. BOX CONTAINS 1 x API Proper pH 7.5 Aquarium Freshwater Stabilizer 260 g See moreUse when setting up a new aquarium, adjusting pH in an established aquarium or changing water. Use exclusively in freshwater aquariums that do not contain live plants. Removes toxic compounds from tap water to make it safe for fish. Sets and stabilizes water pH to 7.5 to help keep fish healthy and colourful. Contains one (1) API PROPER pH 7.5 Freshwater Aquarium Water pH Stabilizer 260-Gram Container.