text: 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 ) .
simplified: 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 ) .