Blue Planet pH Down is a water conditioner designed to lower the pH levels of water in fresh and marine water aquariums. This effective solution is non-toxic and safe for use around fish and plants and helps to improve the quality of tap water in your fish tank by reducing the alkalinity of water for an optimal living environment. Features Highly effective water treatment reduces pH levels in your fish tank. Improves quality of water to meet the requirements for fresh and marine water species. Helps prolong lifespan and increase quality of life for fish and plants. Provides species with the optimal environment to grow and thrive. Acidic formula gradually reduces alkali levels to optimal measurements. Safe to use without harm to aquatic life. Comes complete with instructions for easy use. Active ingredient: 1000g/kg Sodium Phosphate Monobasic.