Grams of salt

[Cory]

How many grams of salt do I need to make 35ppt seawater in 21 gallons of water?

 

[Aaron hacking]

3,047.52? According to redsea coral pro

 

[JimWelsh]

It really depends on the salt mix, and how much water of hydration is in the salts they used.

EDIT: This might help: https://www.hamzasreef.com/Contents/Calculators/DirectSaltCalculator.php

 

[Cory]

Thanks guys. The calculator says 7.44 us pounds or 3374 grams. Want to see if my refractometer measures 35ppt after this.

 

[Cory]

So that weight gave me exactly 35ppt on my refractometer.

 

[Randy Holmes-Farley Verified Community Expert]

As Jim noted, this will often not work, because it depends on the hydration level in salts like magnesium chloride, magnesium sulfate, and calcium chloride used in the mix. Some contain a lot of moisture, and some not so much.

While the link gives corrections for some salt brands, these are old (1999) and may be different now, or may change without notice in the future.

 

[jason2459]

Yep, what they said. lol


but FWIW it took me ~46g to mix up to 35ppt for Instant Ocean in 1 L of RO/DI water.

 

[Jlobes]

Thanks guys. The calculator says 7.44 us pounds or 3374 grams. Want to see if my refractometer measures 35ppt after this.

sounds about right. I use RSCP and add salt to water to get just about 25 total gallons. I add 3550 grams to get 35ppt.