Spectrastone Permaglo Rainbow Aquarium Gravel for Freshwater Aquariums, 2-Pound Bag Go to amazon.com Related posts How to buy the best rainbow fish tank gravel? FeatureWill not affect PHSafe for use in freshwater aquariumsNon-Toxic coating DescriptionPermaglo rainbow aquarium gravel for freshwater aquariums. Will not affect PH. Safe for use in freshwater aquariums.