When you buy new aquarium sand or gravel it is highly recommended that you rinse it first, unless it is live sand for your reef. Even if it says it was pre-washed, it will still carry some dirt which can cause a cloudy mess in your water. However, even after you get it in the aquarium it’s not over, the substrate will accumulate detritus, decomposing organics and more. So here are a few tips on how to clean sand or gravel to keep a pristine aquarium.
How to clean new substrate:
Cut the bag of sand open and fill a 5 gallon bucket about 1/3 full with sand. Place the bucket under the faucet and turn it on full so that it vigorously jets into the sand. Move your fingers through the sand, stirring it and lifting into the water jet as you do so. When the bucket is full, turn off the water, run your fingers through the sand some more, then pour the dirty water away (being careful not to pour the sand down the drain) and repeat. It may take 10 or more goes until the water remains clear. Pour the clean sand into the bare, new tank, and fill the bucket with the second third of sand. Repeat, and repeat again with the last third. You may also do this process outside with a garden hose. If you are rinsing sand for a reed tank I recommend doing your final rinse with RODI water.
Cleaning substrate in an established aquarium:
One of the most trusted methods is to use a gravel cleaner like an Aquaeon Siphon Vacuum or Python Pro-Clean to siphon out detritus into a bucket. You may also use a larger system such as an Aqueon Water Changer or Python No Spill Clean and Fill which connects to your faucet to siphon the water. Once a siphon is achieved, hover the wide open end of the vacuum over the substrate so that it travels a few inches up the tube and releases the detritus from within it. Slowly move the vacuum upwards and gravity should drop the sand or gravel back down, otherwise the flow may be controlled by simply pinching the soft tubing; the detritus should be all that ends up in the bucket. Repeat this, moving the gravel vacuum back to front, left to right, until a sufficient amount of the substrate has been cleaned.
If you don’t have a gravel vacuum, routinely run your fingers, a plastic rod, or a JBJ Aquascraper 4-in-1 Cleaning Kit through the gravel to dislodge debris. Let the filter remove the dirt from the water via mechanical filtration, then clean the filter or swap filter socks to export the dirt and nutrients from your system.
Lastly, use livestock to help clean the substrate. For freshwater use Corydoras catfish, Loaches or Geophagus cichlids to sift the substrate for food, cleaning it as they do so. Tanks containing Corydoras always have cleaner substrates. For nano freshwater tanks, shrimp do a great job. For a reef cleanup crew use Nassarius snails, sand sifting starfish, fighting conchs, or sand sifting gobies to clean the sand.