Estes Spectrastone Permaglo Rainbow Gravel by Estes Sold out $30.56 select a variant 5-lb - Translation missing: en.products.status.sold_out select a variant 5-lb Title 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Sold out Spectrastone Permaglo rainbow is an ideal substrate for fresh water and marine tanks. Our Permaglo colors use silica quartz which is an inert stone that will not affect pH.IngredientsN/A