How much sea salt do you add to 1 gallon of water to get the specific gravity to exactly 1.009? said:Can't go by that. Has to be far more accurate. You really need a refractometer.
Hmmm...maybe I'm not asking this right. I do have a refractometer. I've lowered my QT tank to 1.009 by slowing adding aged RO/DI water. Now I want to keep the water at 1.009 with regular water changes except I'm not sure how much salt to use when I'm mixing it up. said:OH. In that case I start with 1/4 normal or now use 1 cup to make 8 gallons or adjust as needed.