Add one measuring spoon (10 ml) of Pro-Coral Kalk to 1.3 gallons of reverse osmosis water and mix by stirring or shaking the container. Do not aerate! After the undissolved lime has settled, slowly pour the remaining clear solution into a well-flowing area in the tank, preferably one drop at a time. Prepare fresh limewater every day. The water that has evaporated can be replaced on a daily basis with limewater. When filling the tank, check that the pH level does not exceed 8.4 as this can lead to precipitation. Ideally, limewater should be added at dusk or shortly after dark, a s this is when the pH in the tank is at its lowest. The pH level in the tank at night should ideally not drop below 7.9.