Dirted tank (mineralized topsoil)

Also known as: DIY soil substrate, MTS, Walstad method substrate

Properties

pH effect	slightly acidic
KH (carbonate hardness)	softens
GH (general hardness)	neutral
Nutrient load	very high
Ammonia release initially	Yes (cycle the tank before stocking)
Particle size	0.1 to 3 mm
Longevity	5 years before replacement / refresh
Cost tier	low

How it affects the tank

Cheapest possible nutrient-rich substrate: organic potting soil mineralized (dried, wetted, dried again, repeated) for several cycles, then capped with sand or gravel to prevent mud clouds
Releases ammonia for the first 4-8 weeks like aquasoil; needs the same fishless cycling or heavy plant load
Long-term nutrient supply: lasts 3-5 years before depletion, longer than aquasoil
Caps must remain intact: if fish or maintenance disturbs the cap and soil mixes into the water column, the tank becomes a brown mess that takes weeks to settle

Care notes

Diana Walstad's method, from 'Ecology of the Planted Aquarium', is the canonical reference; it uses soil in place of gravel, little or no added CO2 and filtration, modest lighting and a light fish load. The soil must be unfertilized and pesticide-free, mineralized through several wet-dry cycles before placement, and capped with at least 2.5 cm of inert sand or fine gravel. It is not recommended for a first planted tank, since aquasoil is more forgiving.

Plants that work in dirted tank (mineralized topsoil)

50 aquarium plants in the catalog list this substrate as compatible.

Back to aquarium substrate reference

Properties

How it affects the tank

Care notes

Plants that work in dirted tank (mineralized topsoil)

Further reading