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Transition From Fresh to Saltwater

© Winston Vaughan Schoenfeld

About half of the questions I receive every day pertain to switching from freshwater to saltwater aquariums. Most want to know what changes in their filtration system and setup is required to change to saltwater. This is a pretty easy answer...everything. With few exceptions, aquarists find that they end up buying just about everything short of an entire new system for a saltwater aquarium. To complicate matters, if one wants to later upgrade to a reef aquarium, more changes are required. I will try and give those of you out there a little insight into what is involved in changing from a fresh to saltwater aquarium.

Let's take a look at a typical freshwater setup. Usually it will consist of an aquarium between 10 and 50 gallons, a box overflow filter which hangs on the back of the aquarium, rather low-intensity lighting and a bunch of gravel for the substrate (not to mention the fish). So, what out of this is salvageable when transferring to a saltwater aquarium? The answer is the aquarium, if it is at least 30 gallons in size. Generally, the lighting, filter and substrate will need to be changed. You will need at least new lighting - usually an actinic blue bulb and a full spectrum bulb (minus red light). This will provide the beauty and intensity of life for a FISH-ONLY saltwater aquarium. The substrate should be crushed coral or something similar. This substrate provides some area for the bacteria in the aquarium to colonize. These bacteria are what keep the biological cycle in the aquarium stable. As for the filtration system, generally you should look into getting a wet/dry trickle filter. If you want a convenient alternative, try the less popular undergravel filter. You should be able to salvage the heater from your freshwater aquarium and the thermometer but you will need to invest in salt for the saltwater and a hydrometer to test salinity. The pH and chemical test kit that you had for freshwater will also need to be replaced with a saltwater kit. You should, however, be able to keep and use that gravel vacuum, although it will take a little more attention to keep from vacuuming up the crushed coral.

The change gets even more dramatic for a reef aquarium. Whether changing from freshwater or saltwater, there are still a great number of investments that you will need to look into. First, I recommend building your own sump box, which will function as the filtering system for the aquarium. This will also require the addition of a protein skimmer, which can cost well over $100.00. As if this weren't enough, the lighting of the aquarium is much more complex than that for salt and freshwater aquariums due to the fact that the inhabitants of the reef aquarium rely on the lighting as a source of energy and life. Generally, you will need between 3 to 5 watts of lighting per gallon, much more than what you will generally find in freshwater and even saltwater aquariums.