Rocks can enhance an aquarium's appearance.

In summary, here’s what you need to avoid when getting rocks for your aquarium:
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This guide is for curing aquarium rocks in a new tank; a tank that is not yet established and does not contain livestock or corals yet:
Even small aquarium rocks used as substrate should be cleaned regularly.
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Though it may seem that there are a lot of restrictions when selecting a rock for your home aquarium, there is quite a huge selection of rocks that is safe for your aquarium. These rocks can easily be found in most areas and are can easily be identified. Soak the aquarium rocks and decorations in the bucket of cleaning solution for about 15 minutes.
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Photo provided by Flickrcichlid tank landscape using aquarium safe silicon and flat slate rocks
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Aside from an abundance of saltwater aquarium keeping information, saltwater live rock could be considered one of the primary reasons so many people are successfully keeping saltwater tanks these days.Most rocks that you find in your yard, in creeks or streams, or elsewhere in nature pose no problems for use in the aquarium. Those few that may cause problems can be identified by applying a few simple procedures or observations. How well saltwater live rock can completely cycle the aquarium has a lot to do with how much rock you have in your aquarium. Many hobbyists try to get at least 1 pound per gallon for fish only tanks () and 2 pounds or more per gallon for a . You'll definitely need to monitor and quality periodically to check for nitrAtes. If your readings are out of the acceptable range for your tank inhabitants you will need to perform to bring the nitrAte levels within acceptable range.In practice, the power of limestone rocks to significantly raise the pH in an aquarium appears to be rather limited. This can be attested by many African rift lake cichlid aquarists who have found that simply having limestone rocks in their tank will not buffer the water up to the levels they may desire.First, the rock must be water-resistant. If it has a tendency to crumble or flake underwater then it will make a mess in your tank eventually. This is easily ascertained. Hose the rock down while scrubbing it with a stiff brush to dislodge all loose surface material. Put it in a bucket of water and leave overnight. The next day give it another vigorous scrubbing. If it continues to shed a significant amount of particles, it is probably unsuitable for your aquarium. Freshwater aquarium rocks should be , meaning they should have no affect on the pH or hardness of your fish tank water. Freshwater habitats are considered soft water, and adding the wrong rocks to your tank would sway your water to be hard; uncomfortable for your fish. An exception to where you can use calcareous rocks that do not contain salt is with African Cichlids and other hard water originating freshwater fish. The rocks type to stay away from is calcereous rocks; these rocks contain calcium and cause pH and hardness boosting in your water. If softer freshwater is desired, it is best to add clean wood which softens water. Inert rocks that look great in your freshwater tank are: