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Thinking about a Saltwater Aquarium?

Drs. Foster & Smith Educational Staff
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Thinking about Saltwater

For most freshwater hobbyists, the next natural step in their aquarium hobby is marine aquariums. Though extremely popular, the notion of setting up a marine aquarium still may seem intimidating or "too difficult" for the average hobbyist, but those days are over. Thanks to technical advancements in filtration and lighting, they are now much easier for beginners to successfully set up and maintain.

Using what you already know
Experienced freshwater hobbyists may find the transition easier than they thought. The basic principles of maintaining a marine aquarium are essentially identical to freshwater aquariums. They both require patience and a general understanding of the environmental conditions needed to successfully support life. Routine testing, regular maintenance, varied diet, and good filtration are all part of proper husbandry common to any aquarium.

Using what you already have
The most notable difference between freshwater and marine aquariums is the higher cost of setup and maintenance. Luckily, fundamental pieces such as filters, filter media, heaters, thermometers, and the aquarium itself can be used. However, make sure they are safe for saltwater use. Some filters and filter media are designed specifically for freshwater and may corrode or simply fail to work in a marine environment. If you are setting up a Fish-Only or Fish-Only-With-Live-Rock (FOWLR) aquarium, you can also use your current lighting system.

Since the first venture into saltwater is usually a Fish-Only aquarium without light-sensitive corals or invertebrates, the typical freshwater lighting fixture will work well for a Fish-Only marine setup, although you may want to consider color temperature output(K rating) better suited for marine set-ups.

Fish-Only or FOWLR
Aquarium Parameters
Parameter Suggested
Specific Gravity 1.020 - 1.025
Temperature 72 - 78°F
pH 8.1 - 8.4
Alkalinity 8 - 12 dKH
Ammonia (NH3) Undetectable
Nitrite (NO2) Undetectable
Nitrate - Nitrogen (NO3) < 30 ppm
Phosphate (PO4) < 1.0 ppm

Basic equipment and care requirements
Quality marine aquarium salt, a hydrometer, and a marine test kit are the most basic and essential items you will need. Saltwater needed to successfully house marine species has to be carefully mixed and tested. Make sure the specific gravity is 1.020-1.025. As with freshwater, a stable temperature is required before fish can be introduced. Many marine fish are sensitive to water conditions and closer attention to water quality may be required for success.

In addition to your existing filter, supplementary filtration, provided by a protein skimmer, is highly recommended to ensure ideal water quality. Protein skimmers actively remove dissolved organic compounds from the water before they have a chance to break down and compromise water quality.

As for substrate, an aragonite sand bed, usually made from crushed corals, is recommended. It not only adds a natural aesthetic appeal but also helps supplement biological filtration and pH buffering. For an even more natural look, consider adding live rock. Live rock is coral rock that supports encrusting life and provides food, shelter, visual appeal, and biological filtration to keep your aquarium clearer and cleaner.

There are endless possibilities with marine aquariums but the best approach is to start simple. Move to more ambitious setups as you gain confidence and experience in this richly rewarding hobby.


  • Test Kits guide you through aquarium cycling. They cue you when ammonia and nitrite levels have bottomed out, so you can add your livestock.
  • LiveAquaria® Professional Reef Salt contains necessary major, minor, and trace elements for a thriving marine aquarium.
  • Deep Six Hydrometer: easy-to-read swing-arm hydrometer makes accurate measuring of specific gravity and salinity simple.

Will I be able to use the equipment I have from my freshwater aquarium to set up a saltwater aquarium?
Fundamental pieces such as filters, heaters, thermometers, and the aquarium itself can be used for saltwater applicatons. Make sure they are safe for saltwater use and new filter media is used. All saltwater aquariums require a minimm investment in a quality marine aquarium salt, a hydrometer, and a marine test kit.


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