Proper Substrate for a Saltwater Aquarium

When buying saltwater fish, it's important to understand that the setup, care and maintenance of saltwater fish is much more involved than with typical fresh water fish, such as a goldfish or guppy. Saltwater fish require very specific, stable environments to survive. One important aspect of providing this environment is choosing the correct ground covering, or substrate.

  1. Crushed Coral

    • Crushed coral is one good source for a saltwater substrate. Crushed coral can especially benefit saltwater tanks that have live coral. As calcium carbonate is slowly released from the crushed coral, it can promote new growth in the live coral. Calcium carbonate also helps to maintain the high pH level required by saltwater fish.

      Crushed coral needs to be rinsed before being placed in the salt water tank to prevent coral dust. Excess coral dust can cause the tank water to become cloudy as it's placed into the tank, as well as every time the substrate is disturbed thereafter.

    Aragonite

    • Aragonite gravel is a live product that can also be used as a saltwater substrate. A substrate is considered live when it contains beneficial organisms and bacteria. With a grain size of between .25 mm and .50 mm, aragonite gravel can be a more effective buffering agent than other substrates, meaning its high calcium carbonate content has a better ability to help control common pH problems in fish tanks. Artificially colored hobby gravel should be avoided in a saltwater tanks as the product typically lacks the buffering capabilities of live marine substrates. Like other substrates, the product should be rinsed before being placed in the tank.

    Fine-Grained Sand

    • Fine-grained sand can also be used in saltwater tanks as a substrate, although sand does not provide as hospitable environment to the important bacteria and organisms that can benefit your saltwater setup. When using fine-grained sand, it's important to use a different filtration source than an undergravel filter, such as an outside power filter. This will prevent filter clogging or damage.

    No Substrate

    • Consider not using a substrate at all. Most saltwater fish (such as clown fish or angel fish) do not need a substrate to survive. A substrate is often used more for aesthetic purposes, or to hold rocks and coral in place. In some cases, says PetUniversity.com, substrate may just trap fish waste. This can raise the nitrate level of your tank without the correct filtration system, such as an undergravel filter.