How it works
Substrate is usually sold in bags measured by volume (liters) or weight (kg or lbs). To figure out how many bags you need to buy, you must first calculate the geometric volume of the substrate bed based on your tank's footprint and how deep you want the sand or gravel to be. Enter those dimensions to get your required substrate volume in liters and its approximate weight in kilograms.
Example
Scenario: You are setting up a standard 60cm tank (60cm x 30cm) and want a thick 5cm bed of aqua soil for planted aquarium.
- Footprint: 60cm length × 30cm width
- Depth: 5cm
- Calculation: (60 × 30 × 5) / 1000 = 9 Liters of substrate.
Verdict: You should buy one standard 9L bag of aqua soil (like ADA Amazonia or Tropica) to achieve a 5cm depth.
FAQ
How deep should my substrate be?
For a fish-only tank with artificial decorations, 2-3cm (1 inch) is usually enough. If you are keeping live plants with deep roots, you should aim for 5-8cm (2-3 inches) of depth.
Why does the weight vary so much?
Different substrates have different densities. Porous aqua soil or volcanic rock is very light (closer to 1kg per Liter), whereas fine silica sand or dense gravel is heavy (closer to 1.5kg or 1.6kg per Liter).