L.E.C.A. (Lightweight Expanded Clay Aggregate)
Great choice for opening up your mix! I wish they made that "porous baked clay" in gritty sizes, like 2 to 3 mm.
Did it produce a lot of dust and tiny particles when you broke it up?
Brand names:
Geolite, Grorox, Hydroton,
Hydrock, Haydite, Norlite
This is the generic name I see most often around the USA: "Lightweight Expanded Shale, Clay and Slate (ESCS) soil conditioner".
The manufacturers' association is
http://www.escsi.org/Default.a...
They seem to think that a rotary kiln is THE way to manufacture this stuff.
