How To Set Up a 100 Gallon Fish Only Saltwater Tank

Saltwater tanks can add a touch of beauty to a home that most freshwater tanks simply cannot match. Having a marine aquarium allows you to display such iconic animals like clown fish, lionfish and various tangs. However, saltwater tanks are typically far more difficult to set up and manage than a freshwater tank. If you are looking to establish a fish-only aquarium, though, without using live rock or coral, then things become much easier.

Things You'll Need

  • 100 gallon aquarium
  • Dechlorinator
  • Marine salt
  • Wooden mixing spoon
  • Hydrometer
  • Substrate (sand, crushed coral, or gravel)
  • Canister filter
  • Aquarium heater
  • Saltwater test kit
  • Various plastic plants/other decor
  • Fluorescent light strip
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Instructions

    • 1

      Set the aquarium in a location away from direct sunlight. Basements typically work very well. Too much direct sunlight will promote algal growth, which can be an extreme nuisance, especially in fish-only aquariums where there will be no algae-eating invertebrates.

    • 2

      Distribute the substrate in an even, inch-deep layer at the bottom of the aquarium. Gravel should be rinsed under freshwater first to alleviate any dust or debris and sand should be mixed with water in a bucket before it is placed into the aquarium. Mixing the sand with water will keep sand from floating in the aquarium once it is filled. Floating sand could clog a filter.

    • 3

      Fill the aquarium with freshwater until the water line is about an inch below the top. If you used sand as your substrate, push down any floating sand with your fingers until it sinks to the bottom.

    • 4

      Add marine salt. The proper dosage will depend on the manufacturer of the salt (Instant Ocean is a popular choice) as salt is typically sold in batches according to how many gallons of water needs to be salted.

    • 5

      Mix the salt around the aquarium until most of it has been dissolved. This process may take awhile and most of the salt will most likely be dissolved once you apply the filter.

    • 6

      Add the proper dosage of liquid dechlorinator. This product, which comes from many manufacturers, alleviates chlorine and other harmful chemicals in the water and is available at many pet stores. The proper dosage should be indicated on the packaging and varies with manufacturer.

    • 7

      Install the canister filter. Canister filters use two tubes (an input and an output) to take water from the aquarium, filter it, and then expel cleaned water back into the tank. These filters typically sit on the outside of the aquarium and installation instructions vary according to manufacturer. The canister filter must be sized for a 100 gallon tank and preferably a little higher for better optimal filtration.

    • 8

      Allow the filter to cycle for at least 48 hours, which should also dissolve all of the salt. After this time, measure the salinity of the water using the hydrometer (instructions should be on packaging) and test all of the water parameters (like pH) using the saltwater test kit and make any necessary adjustments.

    • 9

      Add plastic plants and other artificial decor along with a light strip, which should sit across the top of the tank over the aquarium's hood, and the submersible heater, which will stick to an inside wall of the tank using suction cups.

    • 10

      Allow the aquarium to cycle for at least a month before considering adding fish.