How much

How much rock for a 40 gallon long?

Pre-calculated for the 40 gallon long (48 × 12 × 16 in · water volume ≈ 34 US gal).

By scenario

ScenarioAmount
Minimal aquascape (0.5 lb/gal)

17 lb

Modern open-aquascape look. Pillars, arches, lots of swimming space. Adequate filtration when paired with sump + skimmer.

Standard reef (1.0 lb/gal)

34 lb

Classic reefkeeping rule of thumb. Plenty of biofiltration, ample coral mounting surface.

Heavy rockscape (1.5 lb/gal)

50 lb

Old-school 'wall of rock' approach. More biofiltration than needed in a modern setup, but works.

Dry rock (TBS, Marco, BRS Reef Saver)

Same lb, different curing time

Dry rock needs 4–12 weeks of cycling to colonize bacteria. Live rock from a reputable source ships with pods, sponges, and ammonia-oxidizing bacteria already on it.

Brands hobbyists actually use

Dry rock cycles 4–12 weeks. Pre-seeded synthetic skips the wait.

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Last reviewed