If you’ve been reading this website for any length of time, there’s probably not much that we need to tell you about how to mix seawater for a mini reef aquarium or saltwater fish tank. There’s countless how-tos on mixing saltwater for a home aquarium display but we thought it was about time we made one of our own for the coming decade of the twenty twenties.
Preparing life-supporting seawater for use in aquariums is more than just mixing the salt as the aquarist also needs to consider the purity of the starting water, achieving an accurate salinity, and bringing it to proper temperature. For all the guides on how to keep a saltwater aquarium, there’s not nearly enough emphasis on getting the salt part of seawater really right.
You can’t master any part of reef aquarium chemistry if you’re still measuring your ‘salinity’ (33 to 35ppt) by using specific gravity (1.023 to 1.026). Testing seawater salinity is one of the easiest tests to perform, yet there’s so much more discussion about maintaining mineral balance and keeping nutrients at a minimum.
For some reef tanks populated with slower growing, soft corals maintained under lower light and lower energy overall, the mineral demands may be so low that water changes alone may be enough to reset the oft talked about calcium, alkalinity and magnesium. We strongly believe that nailing the salinity part of a saltwater tank, and maintaining a proper, stable temperature is not just the first step in starting a healthy reef aquarium, but it shouldn’t fall by the wayside in the long term maintenance of all saltwater aquariums either.