Hi Linda, and welcome!
I use the expanded clay (Hydroton). While it is more expensive, I’ve found it easy to use, and it was readily available here in Knoxville at http://www.innovativehydroponicsupply.com/ways-to-grow/aquaponics/ near the airport. I found the staff helpful as they have 2 Systems setup and running, so in the customer service department, they know what they are talking about. They also carry http://www.theaquaponicstore.com/ products which I’ve also purchased both here locally and online. (not affiliated with these companies, but I like their products and great customer service)
Linda Cook said:Hey Guys. Just joined. I am in Sparta. Just set
Up my IBC containers. Any advice on a grow medium. All the gravel here is limestone and I understand that is not a good medium.