A black substrate, of volcanic origin. The granules are 2-5 mm in size and highly porous. Unlike silica sands, the substrate does not compact and contains enough oxygen, essential for plant roots and filtering bacteria. Plant roots easily grow through the substrate and draw nutrients from the floor. Better water flow also ensures an even distribution of nutrients and temperature throughout the floor.

Unlike so-called Japanese substrates (dried, enriched clays), it does not release excess nutrients into the water. Extremely frequent water changes (2-3 times a week) are therefore not needed in the early stages of setting up an aquarium. Dried clays also tend to bind substances dissolved in the water intensively. This makes things more complicated, for example when treating fish and fertilising plants, where above-limit fertilising, mainly with potassium, becomes necessary.

Chemically neutral, containing only trace amounts of Fe and Mn (mmol/l).
The substrate is porous = it does not compact, and conducts nutrients and oxygen well.
Perfect for plant rooting and growth.
The porous substrate is an ideal home for filtering bacteria that clean the water = a healthy, clean environment for fish and plants.
100% natural.
Holds its shape - suitable for creating striking hardscapes.
Does not crumble.
Does not release nutrients into the water - frequent water changes are not necessary.
Easy to handle.

Grain size: 2-5 mm