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Turning Your Freshwater Aquarium Into A Saltwater Aquarium

Care and maintenance

Saltwater

September 26, 2020

If you plan on turning your freshwater aquarium into a saltwater aquarium, you are likely wondering if the equipment you already have can be used to create that saltwater aquarium or if you have to get brand new equipment. We will examine the individual components to see what you can continue to use and what you must replace. First, we will check out the aquarium itself.

Aquariums are not designed only to be used as either a freshwater tank or a saltwater tank; most aquariums can be used for either. The glass or acrylic material that makes up the structure of the aquarium certainly applies to both freshwater and saltwater aquarium tanks. The silicone adhesive that is used in construction is also applicable to both freshwater and saltwater aquariums.

The one main difference between freshwater and saltwater tanks is that freshwater tanks tend to be considerably smaller than their saltwater counterparts. While a 5-gallon freshwater tank can theoretically be transformed into a saltwater tank, small saltwater tanks are often harder to work with, which is why many experienced saltwater aquarists suggest that you use no smaller than a 55-gallon tank for your saltwater aquarium.

Regarding the filtration of your aquarium, filtration is a little more involved when it comes to saltwater aquariums, since biological filtration is an especially critical component in a saltwater aquarium. Freshwater aquarium owners can choose to use a biowheel and box that hangs on the outside of the tank or in a corner of the tank for filtration needs, but a saltwater tank usually needs more filtration than that which these types of filters can provide. While undergravel filter (UGF) set-ups can be used in saltwater aquariums, they can contribute to unwanted nitrate problems in later years, which is why many saltwater aquarium owners prefer wet-dry trickle and canister type filters that have bio-media chambers.

There is no set choice for a filter to be used in a saltwater aquarium; your best bet is to research the various filtration methods and set-ups, than choose the one that you feel will work best for your aquarium.  You can usually help to narrow your decision by deciding whether you will have a fish-only aquarium or a reef tank system, though filters that are used for reef tank systems can also be used for fish-only aquariums, so you can save money and hassle by purchasing filters that will work with reef tank systems even if you only initially plan on having fish in your saltwater aquarium.

Regarding pumps and powerheads, most freshwater pumps can work well in saltwater aquariums, provided that they are rated as safe to use in saltwater. The main difference between freshwater and saltwater aquariums is that saltwater aquariums use more pumps and powerheads to obtain greater movement and circulation in the water. This can be especially beneficial to the health of corals.

Many freshwater aquarium owners use large-sized gravel or rock material to provide the biological filter base. However, this does not work well in a saltwater tank, as the substrate that is used in saltwater tanks should have high natural levels of calcium content that originates in the ocean. One solution that you can use in both freshwater and saltwater aquariums is ONEdersave’s EcoBio-Block® aquarium products. Their EcoBio-Stone™ M works especially well in saltwater tanks, as it is made to be used in 16 to 50 gallons of water.

The lighting used for freshwater tanks can work with fish-only saltwater tanks, though the light hood may not stand up well to the corrosive effects of saltwater, plus it will not hold MH, PC, or VHO lighting.  You certainly need to change the lighting if you plan on having a reef system. It is important that you carefully research exactly what you need for your aquarium before heading out to your local fish store so that you don’t buy unnecessary or inadequate equipment.

You will definitely need to change the decorations in your tank if you plan to convert from freshwater to saltwater, as most saltwater fish are grazers, and if you leave decorations that are made of plastic, your saltwater fish could have their digestive tracks shut down from eating such items. You should place either live rock or non-living or synthetic decorative rocks and corals in your saltwater aquarium.

The heater for your freshwater tank will likely suffice for your saltwater tank, provided that it is safe to use in saltwater tanks. You will need to use a different test kit, however, since the chemicals used in freshwater test kits are entirely different from those found in saltwater test kits.

In conclusion, some equipment from your freshwater aquarium will work well with your new saltwater aquarium, but some equipment will have to be replaced. By doing some careful research online and in saltwater aquarium books, along with the information in this article, you should be able to transform your freshwater aquarium into a saltwater aquarium quickly and at relatively little cost.