Substrates

Main types:
• Dry aragonite: to be rinsed before use; contributes to long-term buffering.
• Live sand: already inoculated with microfauna and bacteria (do not rinse).
• Special grade granules: less likely to "fly around" with strong flow.
• Crushed coral: coarser grain, suitable for fish-only tanks.

Recommended grain sizes (indicative):
• Fine/oolitic ~0.5–1 mm → deep sand beds and sifting fish like gobies (fam. Gobiidae).
• Medium ~1–2 mm → mixed reefs with good circulation.
• Coarse ~2–4 mm → fish-only tanks or high-flow areas.

Sand bed thickness:
• Shallow 1–2 cm → aesthetic, easy to siphon.
• Standard 2–5 cm → most common solution in mixed reefs.
• DSB (Deep Sand Bed) 10–15 cm with fine sand → better in a dedicated refugium.
Alternatively, you can opt for a bare-bottom tank, focusing on intense flow and skimming.

Setup & maintenance: rinse dry sands with reverse osmosis water until the water is clear; do not rinse live sand. When filling, pour water slowly (onto a plate/bag) to avoid cloudiness. During maintenance, perform a surface siphoning in exposed areas, leaving deep areas of DSBs intact.

Compatibility with fauna: suitable for sand-sifting gobies (fam. Gobiidae), burrowing wrasses at night (fam. Labridae), "strombs" or snails of the genus Strombus (e.g., Strombus spp.) and sea cucumbers (class Holothuroidea) that help stir the surface. Avoid overly coarse grain sizes with small sifters.

Useful notes: aragonite can help maintain stable pH; avoid soil/peat or materials unsuitable for marine aquariums. When dosing bacteria or performing treatments, follow the manufacturer's instructions for carbon, resins, and UV sterilizer (to be turned off during many treatments).