We are making a minor change to make the process a little easier and to save a few dollars. The idea is make about 48 gallons of new salt water at one time. We will stay with a 24 gallon saltwater change monthly, and store the other 24 gallons for a month for the next saltwater change.
A 50-gallon size bag of salt mix is not that heavy to handle and pouring one whole bag at a time into the freshwater simplifies the whole process. We let Amazon be our warehouse and order when we need more.
We are now making approximately 48 gallons of RODI freshwater in a 55 gallon drum. Then adding one whole bag of Reef Cystals salt mix pre-measured to make 50 gallons of salt water with a salinity of 1.021 according to the manufacturer.
Why 48 gallons? Our ratio of one whole bag of salt mix to 48 gallons of water gives us around 1.023 to 1.024 salinity. Just where we want it. This allows the live system to drift up to 1.025 to 1.026 without having to worry too much about freshwater top-off which for this system is not yet automated.
BE CAREFUL: Note that we don’t have any sort of auto shut-off on our RODI system. We have to stay close and monitor the last few gallons in this 55 gallon drum to avoid an over flow. Each rib on the drum is 10 gallons, and we want to make about 48 gallons of freshwater.
Budget: Reef Crystals, 50-gallon size, $14.29; so about $7/month for a salt mix