How much gravel for a 10 gallon tank?
20 × 10 × 12 in · freshwater planning
10 gallon · gravel & substrate
10 gallon equipment and layout plan
A rectangular layout supports a straight front swimming lane and a rear equipment zone. The 20 × 10-inch base has an aspect ratio of 2:1. A lid or light must span roughly 20 inches; measure rim openings and bracket adjustment before ordering.
| Level bed | Sand bags, rounded up | Aquasoil bags, rounded up |
|---|---|---|
| 1 in | 11.57 lb / 1 × 20 lb | 3.28 L / 1 × 9 L |
| 2 in | 23.15 lb / 2 × 20 lb | 6.55 L / 1 × 9 L |
| 3 in | 34.72 lb / 2 × 20 lb | 9.83 L / 2 × 9 L |
To build a slope along the 20-inch front, calculate a shallow 1-inch strip and a deep 3-inch rear bank. Their average depth is 2 inches if the slope is linear across 10 inches. Buy 6.55 L before accounting for rocks. Soil counts assume 9 L packages, not a guaranteed bag weight.
Moving up from the 5.5 gallon changes square inches of substrate coverage from 128 to 200: an increase of 56.25%. Budget for the larger requirement rather than reusing the smaller plan unchanged.
First decisions for this small setup
Lay out the 20-inch front edge before pouring substrate. Keep a clear strip where the siphon will reach, and place heavy hardscape securely rather than relying on loose gravel to hold it upright. Rounded-up bag totals leave surplus: do not pour every bag in just because it was purchased.
The working
20 × 10 × 2 = 400 in³. Divide by 1,728 and multiply by 100 lb/ft³ = 23.15 lb. Round up to 2 bags of 20 lb.
| Depth | Gravel lb / 20 lb bags | Sand lb / 20 lb bags | Aquasoil lb / L |
|---|---|---|---|
| 1 in | 11.57 / 1 | 11.57 / 1 | 6.94 / 3.28 |
| 2 in | 23.15 / 2 | 23.15 / 2 | 13.89 / 6.55 |
| 3 in | 34.72 / 2 | 34.72 / 2 | 20.83 / 9.83 |
Assumptions and limits
The old 1 lb/gal for roughly 1 inch and 1.5–2 lb/gal for 2 inches rules are loose shopping shortcuts. Here a 2-inch bed is 2.31 lb per nominal gallon. Footprint and bulk density explain the difference. Gravel and sand use 100 lb/ft³; aquasoil uses 60. Check bag coverage; grain size and moisture change density.
Bulk densities are stated planning assumptions; litre conversion: NIST conversion tables
How to use this plan
- Measure the inside footprint; this plan uses 20 by 10 inches.
- Choose an average depth, allowing for slopes and hardscape.
- Calculate volume and mass as above; buy about 2 20 lb bags for a level 2-inch gravel bed.
Adjust measurements with the gravel & substrate calculator
Questions before you buy
What dimensions does this 10 gallon calculation use?
It uses a rounded 20 × 10 × 12 inch rectangle. Actual dimensions vary by brand and frame; measure your own tank.
What is the gravel & substrate estimate for a 10 gallon tank?
23.15 lb gravel for a 2-inch bed
Equipment to check
Compare aquarium substrate. Check dimensions, capacity and product instructions before buying.
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