Inert gravel
Also known as: Aquarium gravel, Quartz gravel, Pea gravel (smooth)
Properties
| pH effect | neutral / inert |
|---|---|
| KH (carbonate hardness) | neutral |
| GH (general hardness) | neutral |
| Nutrient load | none |
| Ammonia release initially | No |
| Particle size | 3 to 8 mm |
| Longevity | indefinite |
| Cost tier | low |
How it affects the tank
- No nutrient capacity: stem plants and root feeders need root tabs or extensive water-column dosing to thrive
- Larger particles let mulm settle into the substrate; needs gravel vacuuming during water changes or anaerobic zones develop
- Vinegar test before stocking: if the gravel fizzes when wet vinegar is dropped on a few stones, it contains calcium carbonate and will raise pH/KH (treat it as limestone gravel instead)
- Compatible with most fish; only sand-sifters dislike the larger particles
Care notes
Generic dyed aquarium gravel from pet stores works but the coating can flake over years. Untreated quartz gravel from landscape suppliers is cheaper and lasts forever. Avoid pink/red gravel that may be limestone (use the vinegar test).
Plants that work in inert gravel
39 aquarium plants in the catalog list this substrate as compatible.
- African water fern
- Amazon frogbit
- Ambulia
- Anacharis
- Anubias barteri
- Anubias congensis
- Anubias nana
- Anubias nana petite
- Aponogeton ulvaceus
- Bacopa caroliniana
- Bacopa monnieri
- Banana plant
- Cabomba
- Christmas moss
- Cryptocoryne beckettii
- Duckweed
- Dwarf hygrophila
- Dwarf sagittaria
- Flame moss
- Giant hygrophila
- Hornwort
- Hydrocotyle tripartita
- Java fern
- Java fern narrow leaf
- Java moss
- Jungle val
- Ludwigia repens
- Marsh ludwigia
- Pogostemon erectus
- Red milfoil
- Red root floater
- Riccia fluitans
- Rotala indica
- Salvinia
- Subwassertang
- Water lettuce
- Water sprite
- Water wisteria
- Weeping moss
Sources
Data drawn from: aquatic-plant-central. Last verified 2026-05-13.
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