For all you fish enthusiasts out there, introducing the API pH UP Freshwater Aquarium Water pH Raising Solution 4-Ounce Bottle! You know that pH is the measure of acidity of water on a scale ranging from 0 to 14, right? Well, different fish require different pH levels to thrive and certain geographies have tap water conditions that may not be ideal for your aquatic pets. But fear not! This magical solution raises aquarium pH in freshwater aquariums to the desired level.