Having never owned an aquarium before, I was not aware that water needed to be changed on a regular basis. For saltwater, this means making saltwater before performing a water change. See below for how to make saltwater for your aquarium.
Each week, or every other week, water in the aquarium must be changed out and replaced with fresh saltwater. The percentage seems to vary depending on the aquarist; but we have found that 10% each week, or 20% every two weeks seems to be the consensus. One of my first questions about these water changes was “So, we can just use tap water right?” I was surprised when the answer was no, and horrified that I would have to carry gallon after gallon of purified water purchased from the grocery store every week, even in the winter, up a flight of stairs and into the house. “No.” was my simple answer. This was a deal breaker for me. There had to be a better way. Well, there is.
This is a 75 gallon per day (GPD) Five Stage Ocean Reef RO/DI System from The Filter Guys of Minnesota. The system provides purified water perfect for saltwater aquariums by filtering your home’s tap water using reverse osmosis and deionization. The unit cost $199.00, which may seem pricey, but when factoring in the alternative cost of gas to run to the store plus the price of the water; this should save quite a bit in the long run. So why is using straight tap water an issue? High levels of nitrate, phosphate, and heavy metals such as copper can cause algal blooms and bacterial problems, as well as be toxic to your fish. Best yet, this saves me having to buy 10 gallons of purified water every week.
We have set this system up in our basement next to our water softener. The RO/DI water will go into the top bin, and we will do our salt mixing in the bottom bin.
One drawback to using an RO/DI system is the water waste involved. For every gallon of RO/DI water made, there are 3-4 gallons of “waste water”. This waste water is not unsafe to use, however, it has higher concentrations of minerals and impurities than your tap water because of going through the filtration process. This amount of waste really bothered me at first, so I did some research on what people do with their waste water. Other aquarists use this water to wash their clothing, water their plants, water their animals, water the lawn, fill fresh water fish tanks, dishes, gardening, car washing, filling pools and hot tubs, etc. There seem to be many uses for this water. These options make me feel better knowing that there are so many options that can be done with this waste water. For now, as it is winter, most of our waste water will go into our sump pump and out to a dry well. I plan on using some for the pets and plants and in the Spring plan on using it for watering the garden.