Bag sizes don’t match tank sizes, and each brand gives its own rule — one in kilograms, one in liters, one in pounds per gallon of water. This calculator applies each rule to your tank and picks the bag combination with the least left over. If you haven’t picked a substrate yet, start with sand + root tabs or aquasoil: for java fern and anubias you may not need aquasoil at all.
Standard tanks at a 2 in bed
| Tank | Bed | Stratum | ADA |
|---|---|---|---|
| 2.5 gal · 12.25 × 6.25 in | 2.5 L | 5.5 lb · 1 × 8.8 lb | 1 × 3 L |
| 5.5 gal · 16.25 × 8.375 in | 4.5 L | 9.8 lb · 1 × 8.8 lb + 1 × 4.4 lb | 2 × 3 L |
| 10 gal · 20 × 10 in | 6.6 L | 14.5 lb · 1 × 17.6 lb | 1 × 9 L |
| 15 gal · 24 × 12 in | 9.4 L | 20.8 lb · 1 × 17.6 lb + 1 × 4.4 lb | 1 × 9 L + 1 × 3 L |
| 20 high · 24 × 12 in | 9.4 L | 20.8 lb · 1 × 17.6 lb + 1 × 4.4 lb | 1 × 9 L + 1 × 3 L |
| 20 long · 30 × 12 in | 11.8 L | 26.0 lb · 1 × 17.6 lb + 1 × 8.8 lb | 1 × 9 L + 1 × 3 L |
| 29 gal · 30 × 12 in | 11.8 L | 26.0 lb · 1 × 17.6 lb + 1 × 8.8 lb | 1 × 9 L + 1 × 3 L |
Footprints are the listed outside sizes; the glass makes the inside a little smaller, so the numbers carry a small margin. A 20 high and a 15 gallon share the 24 × 12 in footprint and need the same amount. Controsoil and Eco-Complete are in the calculator above.
How each brand is calculated
| Brand | Rule we apply | Bags |
|---|---|---|
| Fluval Stratum | Fluval: “length x width x thickness divided by 1000” in cm gives kg | 4.4, 8.8, 17.6 lb |
| ADA Amazonia | Sold by volume: bed liters = cm × cm × cm ÷ 1000 | 3 L, 9 L |
| UNS Controsoil | Buce Plant: inches × inches × inches ÷ 60 gives liters | 1, 3, 10 L |
| CaribSea Eco-Complete | CaribSea: 1–2 lb per gallon of tank water; 2 lb “will deliver the best performance” | 10, 20 lb |
Fluval’s rule treats one liter of Stratum as one kilogram. ADA and Controsoil are sold in liters and we found no weight to cite, so the calculator shows only volume for them. Eco-Complete’s rule depends on the tank’s gallons, not on bed depth; its directions add that “an ideal bed depth is 3"”.
Sloped beds and hardscape
A bed that rises toward the back looks deeper and gives rooted plants more room where they grow tallest. Enter the front and back thickness; the calculator uses the average. For a 10 gallon with 1.5 in at the front and 3 in at the back, that is 7.4 liters, or 7.4 kg of Stratum.
Rocks and wood sit on top of the bed and take up space, but the bed under them still needs filling, so we don’t subtract them. If you build a tall mound behind a large stone, measure that area separately and add it.
What goes into the water after the soil, such as root tabs or liquid fertilizer, is covered in the root tabs or aquasoil guide, with each maker’s dose for 5 and 10 gallons.