By LANDEN Editorial Team · Reviewed by Landen, November 9, 2026
THRIVA Natural Aquarium Soil comes in 5 L bags (about 10 lb each). To find how many bags your tank needs, work out the volume of the layer you want and divide by 5. The pack recommends an average layer of 3 to 8 cm, depending on the size of the tank.
Quick answers
- Bag size: 5 L per bag, about 10 lb.
- Layer depth: 3 to 8 cm on average, depending on the size of the tank.
- Grades: S (about 1 mm), M (about 3 mm), L (about 5 mm) and Mixed.
- Rinsing: the pack says THRIVA does not need rinsing and can be used directly.
Work it out in three steps
- Measure the inside floor. Take the outside length and width of the tank in cm and subtract twice the glass thickness from each.
- Find the litres. Multiply inside length × inside width × the layer depth you want (cm), then divide by 1000.
- Count the bags. Divide the litres by 5 and round up.
Worked examples for LANDEN tanks
| Tank | Outside size (cm) | Glass | Inside floor (cm) | 3 cm layer | 8 cm layer | Bags (3 to 8 cm) |
|---|---|---|---|---|---|---|
| 36C, 11.5 gal | 36 × 36 × 36 | 5 mm | 35.0 × 35.0 | 3.7 L | 9.8 L | 1 to 2 |
| 60P, 16 gal | 60 × 30 × 36 | 6 mm | 58.8 × 28.8 | 5.1 L | 13.5 L | 2 to 3 |
| 60H, 30 gal | 60 × 45 × 45 | 8 mm | 58.4 × 43.4 | 7.6 L | 20.3 L | 2 to 5 |
| 90P, 55 gal | 90 × 50 × 50 | 10 mm | 88.0 × 48.0 | 12.7 L | 33.8 L | 3 to 7 |
Inside sizes are worked out from the outside size and glass thickness, so treat them as estimates.
How deep should the layer be?
The pack gives 3 to 8 cm as an average range and does not split it by tank. As a rule of thumb, go thinner in a short tank so the soil does not take up too much of the height. In a 36 cm tall tank, an 8 cm layer is close to a quarter of the height.
The pack also gives two examples: one bag in a 45 × 30 × 30 cm tank makes a layer about 3.7 cm deep, and two bags in a 60 × 30 × 36 cm tank make about 5.6 cm. Those use the outside size, so a calculation on the inside floor, as above, comes out slightly deeper.
Which grade should I pick?
The THRIVA pack suggests:
- S for tanks of 10 US gallons (about 40 L) or less
- M for 10 to 16 gallons (about 40 to 60 L)
- L for 16 gallons (about 60 L) or more
- Mixed for general use in any tank
Shop: THRIVA Natural Aquarium Soil, 5 L
Laying the soil
- Pour it in dry. The pack says it can be used directly, without rinsing.
- Spread it to the depth you worked out above.
- The pack notes that THRIVA is rich in organic acids and nitrogen nutrients, and that in a new setup it is normal for the water to turn yellow while these dissolve. It says this improves as the plants grow in and cover the soil.
- The pack says to store bags in a dark, damp place at 5 to 25 °C. Once a bag is open, use it in one go or reseal it.
THRIVA and LANDEN Aquarium Soil
THRIVA Natural Aquarium Soil is the current name of the soil LANDEN previously sold as LANDEN Aquarium Soil (also called LANDEN Aqua Soil). It is the same product line. The THRIVA pack splits it into four grades and adds the grade-by-tank advice above. The bag size is unchanged at 5 L, and both packs give the same 3 to 8 cm layer. Some older product descriptions say 6 to 8 cm; use the range on the bag.
FAQ
How many bags for a 60 × 30 × 36 cm tank?
Two to three 5 L bags. The inside floor is about 58.8 × 28.8 cm, so a 3 cm layer takes about 5.1 L and an 8 cm layer about 13.5 L.
Do I need to rinse THRIVA?
The pack says no. It can be used directly.
Is THRIVA the same as LANDEN Aquarium Soil?
Yes, it is the current name of the same product line.