Reef Unit Converter

Quickly convert common reef-keeping units for accurate testing and dosing.

Aquarium Show

Convert between dKH, meq/L, and ppm.

Alkalinity (dKH)

Alkalinity (meq/L)

Alkalinity (ppm as CaCO₃)

1 dKH ≈ 0.357 meq/L ≈ 17.86 ppm (as CaCO₃). These are standard reef chemistry conversions.

Convert between US gallons and liters.

Volume (US gallons)

Volume (liters)

1 US gallon ≈ 3.785 L. Use the volume from your Aquarium Volume Calculator for best accuracy.

Convert between salinity units. Natural seawater is ~35 ppt ≈ 1.026 SG.

Salinity (ppt)

Specific Gravity (SG)

Salinity (PSU)

Approximation: SG ≈ 1 + (ppt × 0.00077). PSU is effectively the same as ppt for reef use. Ideal reef range: 34–36 ppt (1.025–1.027 SG).

Convert between Fahrenheit and Celsius.

Temperature (°F)

Temperature (°C)

Most reef tanks run best between 24–27°C (75–81°F), depending on livestock.