Input (grade 4): Technically, brackish water contains between 0.5 and 30 grams of salt per litre - more often expressed as 0.5 to 30 parts per thousand (ppt or â).
Output (grade 4): Technically, brackish water contains between 0.5 and 30 grams of salt per litreâ "more often expressed as 0.5 to 30 parts per thousand (ppt or â).