Fibredust/HydraFiber line is available in the popular 5kg compressed block, Open Top Bags, Layflat Slabs, and Grow Cubes. Compressed at 5 to 1, just add water and watch it expand to 2.2-2.5cuft. To expand, place in a large container and slowly add 5 gallons of water. Looking for an alternative to inorganic substrates that are difficult to dispose of? This patented product incorporates an engineered fiber created through a thermal process and the coir you love to increase air porosity, water holding capacity, and reduced terbidity.