How much

How much sand for a 40 gallon breeder?

Pre-calculated for the 40 gallon breeder (36 × 18 × 16 in · raw volume ≈ 45 US gal · water volume ≈ 39 US gal).

By scenario

ScenarioAmount
1" shallow / aesthetic bed

32 lb

2 × 20-lb bag. No denitrification. Acceptable for SPS frag tanks.

2" standard sand bed (most reefs)

64 lb

4 × 20-lb bag. Best look-to-maintenance ratio for mixed reefs.

4" deep sand bed (DSB)

128 lb

7 × 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

Aragonite bags. Special Grade is the modern reef default; Pink Fiji is finer.

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Last reviewed