Wow, thank you, that gives me a good idea of the concept, I have to extrapolate that given a large enough volume of larger sized particles must have some sort of effect on water movement through the substrate, although I am agreed that at the ratio given my tank it is just about negligible, however in the root zones the mix of gravel is much more rich probably as much as 30/70 sand to gravel.
Sent from my iPhone using Tapatalk