Enter your enclosure dimensions, pick a substrate recipe, and instantly get per-ingredient volumes, bag counts, and total shopping cost.
How to Use This Calculator
Step 1 — Enclosure dimensions: Enter your vivarium's interior length and width (not total tank size — measure the usable floor area). Then set your desired drainage layer depth (2.5–3 in recommended) and ABG substrate depth (2–4 in typical).
Step 2 — Recipe: Choose a preset or enter custom ingredient ratios. The calculator shows each ingredient as a proportion of the total substrate volume. Edit the "Parts" column freely to dial in your own blend.
Step 3 — Bag sizes and costs: Enter the bag volume and price for each ingredient plus the drainage media. The calculator tells you how many bags to buy (always rounded up) and the estimated total cost.
Step 4 — Shopping list: Copy, download as CSV, or print the result as a clean PDF to take to your local pet or garden store.
About Bioactive Vivarium Substrate Layers
A bioactive vivarium uses living soil to create a self-sustaining miniature ecosystem. Isopods and springtails break down waste, plant roots cycle nutrients, and beneficial bacteria process organic matter — dramatically reducing hands-on maintenance.
Every tropical bioactive build uses the same structural stack, from bottom to top:
1. Drainage layer (LECA/hydroballs): Catches excess water, prevents substrate saturation, and maintains humidity. Aim for 2.5–3 inches.
2. Screen separator: A mesh barrier that keeps substrate out of the drainage layer while letting water flow freely through.
3. ABG substrate layer: The living soil — a blend of structural fibrous materials, moisture-retentive elements, charcoal, and organic matter. Typically 2–4 inches deep for most setups.
4. Leaf litter cap: Provides food and shelter for microfauna, and a naturalistic appearance.
Recipe Presets Explained
ABG Classic (Atlanta Botanical Garden, by Ron Gagliardo): 2 parts tree fern fiber + 2 parts orchid bark + 1 part sphagnum moss + 1 part peat moss + 1 part charcoal. The original benchmark — excellent aeration, long-lasting structure, and proven for dart frog vivariums.
Modern Coco: Swaps peat moss for coco coir (more renewable, less acidic) and adds worm castings for slow-release nutrition. Preferred by many current builders for isopod-heavy bioactive setups.
Arid / Desert: High-sand base with some coco coir and charcoal — suitable for desert reptile enclosures, bearded dragons, or arid bioactive setups that still need microfauna support.
Method & sources: Volumes calculated as: length × width × depth. Substrate ingredient volumes are proportional shares of total substrate volume based on the selected recipe parts. Bag count = ⌈needed volume ÷ bag volume⌉ (always rounded up). ABG recipe proportions from
Dendroboard and
NEHERP Vivarium Construction 101. Drainage layer depth recommendations from NEHERP (2.5–3 inches). All results are estimates; exact amounts may vary by ingredient compression, settling, and enclosure shape. Not veterinary or horticultural professional advice.
Frequently Asked Questions
What is ABG mix and what is the classic recipe?
ABG (Atlanta Botanical Garden) mix is the gold-standard substrate for tropical bioactive vivariums, originally developed for dart frog enclosures. The classic recipe by volume is: 2 parts tree fern fiber, 2 parts orchid bark, 1 part sphagnum moss, 1 part peat moss, 1 part charcoal. A popular modern variant replaces peat with coco coir and adds worm castings for nutrition.
How deep should the drainage layer be?
The LECA or hydroballs drainage layer should ideally be 2.5–3 inches deep. This depth provides enough reservoir capacity to prevent saturation while maintaining stable enclosure humidity. Very small vivariums (under 12×12 inches) can work with 2 inches; large or heavily misted builds may benefit from 3 inches or slightly more.
How deep should the ABG substrate layer be?
Two to three inches is sufficient for isopods, springtails, and most small plant roots. Four to six inches works for larger plants or species that burrow extensively. Very deep substrate (6+ inches) is used in large builds and doesn't harm the system, but isn't necessary for standard setups.
Can I substitute coco coir for peat moss in ABG mix?
Yes — coco coir is the most commonly recommended peat substitute. It has similar moisture retention and aeration, is more sustainably produced, and is slightly less acidic. Use it at the same 1-part ratio in place of peat. Worm castings can also be added (10–15% of total volume) for slow-release nutrients, especially in setups with isopod colonies.
What if I can't find tree fern fiber?
Tree fern fiber is the structural backbone of true ABG mix — its fibrous structure resists compaction for years and creates air channels that fine particles can't. Without it, increase orchid bark proportion. Fine coconut husk chips are a partial structural substitute. Note that without tree fern fiber, the mix will compact more quickly and need replacing sooner.
How much LECA do I need for the drainage layer?
Multiply your enclosure's floor area (length × width) by the drainage depth. For example, an 18×18-inch footprint at 3 inches depth = 972 cubic inches ≈ 15.9 litres. This calculator does that automatically. LECA is commonly sold in 4-litre or 9-litre bags; the calculator rounds up to whole bags.
Should substrate ingredients be sterilized before mixing?
Commercial bioactive ingredients like sphagnum moss, orchid bark, and coco coir are generally safe to use directly. Some keepers freeze individual components for 24–48 hours to kill any insect eggs before mixing, though this isn't considered strictly necessary. Avoid any ingredients containing added fertilizers, pesticides, or perlite with Miracle-Gro, which are harmful to reptiles.