Aquarium Substrate Selection Guide: Soil, Sand & Gravel Compared

Substrate choice affects root nutrition, water chemistry, and livestock behavior. Match texture, nutrient content, and maintenance workflow to your aquascape goals.

Substrate Categories

Type Traits Best Use Cases
Nutrient-Rich Soil Active; releases ammonia initially Dense planted aquascapes
Inert Sand (Fine) Neutral; compacts Corydoras, shrimp grazing
Inert Gravel (Medium) Neutral; good flow through Mixed community tanks
Clay-Based Cap Cation exchange capacity Root feeding enhancement
Specialized Shrimp Soil Buffers pH downward Caridina setups

Nutrient vs. Inert Approaches

  • Active Soil: Provides macro/micro nutrients; may need initial water changes
  • Inert + Root Tabs: Flexible; dose water column + periodic tab insertion

Depth Guidelines

Zone Recommended Depth
Foreground 1–1.5"
Midground 2–2.5"
Background 3–4" (for root-heavy stems)

Gradients add visual depth and keep front scape clean.

Preventing Anaerobic Pockets

  • Avoid >4" deep uniform beds without plant roots
  • Light gravel mixing or Malaysian trumpet snails increase gentle turnover

Shrimp Considerations

Caridina benefit from buffered substrates (stable low pH). Neocaridina thrive in inert sands with steady remineralized water.

Root Feeding Strategy

Plant Approach
Crypts Root tabs at crown quarterly
Swords Multiple tabs around base
Stem Plants Mainly water column; occasional tab cluster
Carpeting Soil or thin nutrient layer for consistent spread

Final Thoughts

Pick substrate for long-term stability, not short-term appearance. Thoughtful layering and nutrient strategy keep roots vigorous and water parameters consistent.