Ppm to mg/L

[sljayvie18]

I'm newbie please help me i have a brackish tank. I need to know the conversion of 300 ppm for calcium and 900ppm for magnesium to mg/L.

 

[Randy Holmes-Farley]

Those units are close enough to treat as the same, and many folks (myself included) mistakenly use them interchangeably.

Strictly speaking 1 ppm = 1 mg/kg

But in 35 ppt seawater, 1 L weighs about 1.023 kg at 25 deg C

300 ppm = 300 mg/kg = 300 mg/kg / 1.023 kg/l = 293 mg/L