Backyard Aquaponics
A place to discuss aquaponics

Maximum voids are created with uniformly sized particles.

Mixed sizes are probably not a good idea. They sell a mix of various sized gravel as road base around here and it is not recommended for AP! *grin*

Small voids (in sand, for example) clog with small solids and bacteria too fast.

Max drainage would take place with large rock (as bacteria and "fish solids" can not clog it), but the voids are too large for seeds, so topping with finer rock (as TCLynx has done) is probably a really good idea....unless you ever mix the rocks..

[quote="hydrophilia"]Maximum voids are created with uniformly sized particles.

Mixed sizes are probably not a good idea. They sell a mix of various sized gravel as road base around here and it is not recommended for AP! *grin*
Somebody in aus decided to use roadside gravel got it all home then set up and found it had been treated with something had to pul the whole thing apart and decontaminate leason learned