Review on 🐠 Seachem Reef Kalkwasser 500g: Essential Calcium Supplement for a Thriving Reef Aquarium Environment by Kim Marshall

Maybe a 2 gallon tablespoon. This container is good for hundreds of gallons. I use it as a PH buffer when changing the water. Your tank's PH is the PH of your tap water, so I make sure to add water that is at least a low to medium water level of 8. I add a cup of clear lime water per gallon or 2 water changes. You can also check the salinity at the same time and just pour everything into the tank. You won't damage anything.