Silicone

[Greg H.]

Originally Posted by Grimm

I did....Seems to be working fine for me.

I think that the main advantage of using leca is because its large particle size allows for easy water flow and the risks of stagnant water are reduced greatly. And it also looks to be lighter weight then gravel so that also helps the back out a good deal when moving a tank around!

Originally Posted by beckdg

actually since the leca is porous it has more surface area for beneficial bacteria. if you're not attempting to overstock it shouldn't really matter much.

perfect spheres also maximizes pore size/voids between the individual grains. this can be beneficial for several reasons. if the roots can't get to it because of sheathing used to separate the layers the only real use becomes easier flow through. different size/shape granules tends to want to fill in the gaps more over time. when used as a sole source of soil this allows for good drainage and an airy soil so roots don't suffocate.

LECA's porous nature also lets it draw water up to the soil / substrate, helping to keep it moist ( even when the water level is lower than the soil / substrate ), while still providing good drainage. I find that to be a nice bonus.