Potting soil

[newton]

Fired bricks in general leach out lime and salts, Kiari absorbs all the lime and salts in the firing process then leaches out the most so it isn't an inert clay material.

The more you water, the more efflorescing salts are transported to the surface of the harder material and thus the plants roots are in direct contact with a compound that is toxic to them.

Just my humble opinion.

[Muhammad Arif Khan]

Your humble opinion is worthy opinion.