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 ("Ecology of the Planted Aquarium") is the canonical reference. Soil must be unfertilized, pesticide-free, mineralized through multiple wet-dry cycles before placement. Cap with at least 2.5 cm (1 inch) of inert sand or fine gravel. Not recommended for first-time planted tanks; aquasoil is more forgiving.
Plants that work in dirted tank (mineralized topsoil)
50 aquarium plants in the catalog list this substrate as compatible.
- Alternanthera reineckii
- Alternanthera reineckii Rosaefolia
- Amazon frogbit
- Amazon sword
- Ambulia
- Anacharis
- Aponogeton crispus
- Aponogeton ulvaceus
- Bacopa caroliniana
- Bacopa monnieri
- Cabomba
- Cryptocoryne balansae
- Cryptocoryne beckettii
- Cryptocoryne lutea
- Cryptocoryne pontederiifolia
- Cryptocoryne spiralis
- Cryptocoryne undulata
- Cryptocoryne wendtii
- Downoi
- Duckweed
- Dwarf four-leaf clover
- Dwarf hygrophila
- Dwarf lily
- Dwarf sagittaria
- Echinodorus bleheri
- Giant hygrophila
- HC Cuba
- Hornwort
- Hydrocotyle tripartita
- Jungle val
- Ludwigia repens
- Ludwigia Super Red
- Madagascar lace plant
- Marsh ludwigia
- Micro sword
- Needle leaf hairgrass
- Ozelot sword
- Pearl weed
- Pogostemon erectus
- Pogostemon stellatus Octopus
- Pygmy chain sword
- Red milfoil
- Red root floater
- Rotala indica
- Rotala rotundifolia
- Rotala wallichii
- Staurogyne repens
- Tiger lotus
- Water sprite
- Water wisteria
Sources
Data drawn from: walstad-ecology-planted-aquarium, aquatic-plant-central. Last verified 2026-05-13.
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