Ideal size for lava rock as grow media

[William Crain Jr.]

So I am setting up my first aquaponics system. I decided to use lava rock for the media. I got several bags for my local hardware store got them home and found out they have many larger rocks mixed with smaller rocks. Some are as large as 1". Will this cause problems for my system? Should I empty the grow bed and look for a different option? Let me know what you think... I was thinking about having the very top layer 3 or 4" of hydroton anyway...

[William Crain Jr.]

Thanks for all the comments been helpful. Now I have to find a local supplier for hydroton at a good price. I was also thinking about using stalite a.k.a. Permatil for the top section of the Grow bed it is somewhat cheaper than hydroton.

[TCLynx]

Stalite or Permatil is good but I recommend an acid soak/rinse before starting up an aquaponic system with it since their kiln process involves hydrated lime so the media will have a temporarily high pH right at the beginning.

[William Crain Jr.]

thanks TC.  I did not know that..