The product formerly known as Hydroton.
When growers purchase a complete hydro system from GH, it comes with a specific growing media: expanded clay pebbles. These marble sized balls of clay are a really unique type of soilless media. Growers love them because they have a good balance between air and moisture, they are sustainable, and easy to use.
Clay, an organic and sustainable material, is shaped into balls, and then fired in an oven at about 1200 degrees. The little balls then puff up like popcorn into air filled pebbles. The clay pebbles are not salty, they are inert. It is still recommended to rinse the pebbles before use to remove any dust or particles first. One of the other great benefits of using the pebbles is that they can be reused. To clean them, either boil them in water, or clean them with a bleach solution.
The reasons to use expanded clay pebbles as a growing media are numerous. Water flows between the pebbles quickly, supplying the roots with nutrients, yet allowing the roots to stay oxygentated. It's the perfect media choice for ebb and flow and drain to waste.