How much sand for a 100 gallon?
Pre-calculated for the 100 gallon (60 × 18 × 20 in · raw volume ≈ 94 US gal · water volume ≈ 83 US gal).
By scenario
| Scenario | Amount |
|---|---|
| 1" shallow / aesthetic bed | 53 lb 3 × 20-lb bag. No denitrification. Acceptable for SPS frag tanks. |
| 2" standard sand bed (most reefs) | 106 lb 6 × 20-lb bag. Best look-to-maintenance ratio for mixed reefs. |
| 4" deep sand bed (DSB) | 213 lb 11 × 20-lb bag. Provides anaerobic denitrification. Old-tank-syndrome risk after 5+ years. |
| Bare bottom | 0 lb Frag tanks, ULNS, maximum-flow setups. Best detritus visibility. |
Brands hobbyists actually use
Affiliate linksAragonite bags. Special Grade is the modern reef default; Pink Fiji is finer.
CaribSea Arag-Alive Special Grade reef sandLive aragonite, no rinse, 1–2 mm grain. Reef default.View on Amazon →CaribSea Pink Fiji aragonite sandPink tinge, fine grain.View on Amazon →Nature's Ocean Bio-Activ Live Aragonite sandCheaper alternative to CaribSea.View on Amazon →
Affiliate links. As an Amazon Associate, reefcalcs earns from qualifying purchases.
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