shookONES is right with the ratio numbers and volume calculation. Here is a basic guideline paper for Kaldnes moving beds (media quantity, volumes, air flow, etc) http://www.raingarden.us/kaldnes_bio.pdf
With Kaldnes - for koi ponds or larger systems people normally calculate the total amount of media required based on size of livestock and feeding volumes.
With Kaldnes - for koi ponds or larger systems people normally calculate the total amount of media required based on size of livestock and feeding volumes.