How much

How much salt for a Standard 29 gallon?

Pre-calculated for the Standard 29 gallon (30 × 12 × 18 in · raw volume ≈ 28 US gal · water volume ≈ 23 US gal).

By scenario

ScenarioAmount
Initial fill (cycling the tank)

7.8 lb (3522 g)

Or about 0.43 × 7 kg buckets / 0.13 × 22 kg buckets.

10% weekly water change

0.76 lb (345 g)

2.3 gal new saltwater. Many reefers settle here as a routine.

20% bi-weekly water change

1.52 lb (690 g)

4.6 gal new saltwater every 2 weeks.

Annual salt budget (10% weekly)

40 lb (17.9 kg)

Plan on 3 × 7 kg buckets per year.

Brands hobbyists actually use

Buckets reefers actually buy at this volume. Coral Pro for high-alk SPS, Pro Reef for low-alk dosing tanks, Reef Crystals for budget mixed reefs.

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Last reviewed