Ron was the original owner of this forum, but he sold it and hasn't posted anything in years. I personally have reservations about using kitty litter myself. In another forum someone posted that they used a mix of kitty liter and a regular
growing medium, and it clumped together (probably the kind that's supposed to be easy to scoop out). But my other concerns are if it's pH stable, and if it will affect the mineral concentrations of the
nutrient solution. I would need to do some sample testing before I considered using it. Some also have chemicals for neutralizing odors (possibly even fungicides etc.) that wouldn't be beneficial in a hydro system.