How To Clean Aquarium Gravel. Add the cups of dirty gravel that you set aside and mix thoroughly with the clean gravel. After doing that, simply rinse the fish tank with some water to clean the glass and put it back in its place.

This method is the most effective if you have algae growing in your substrate, according to fish tank master. For your satisfaction, you can pick a day in a year to drain out the water and do a thorough cleaning of the gravel so they look as good as new. Normally this is pretty easy, and you would use a special siphoning hose called an aquarium vacuum to clean the dirty gravel.