• Saltwater aquariums need strict cleaning to stay healthy.aquarium fish image by Alison Bowden from Fotolia.com
  
  

Clear Benefits

• Vacuuming the gravel in your saltwater aquarium can help to remove food and waste debris that accumulates at the bottom of the tank, and it can help keep nitrate and ammonia levels in check.
  
  

Associated Risks

• Very deep gravel beds (more than 3 inches), especially those composed of fine particles such as aragonite, can develop pockets of anoxic and anaerobic bacteria, which thrive in oxygen-starved conditions. These bacteria in turn produce hydrogen sulfide, a deadly compound that can kill entire tanks when stirred by a gravel vacuum and released into the water column.
  
  

Bottom Line

• While hydrogen sulfide pockets do exist, they take a long time to develop in the gravel bed and almost never occur in tanks with gravel larger than 2mm. Overall, regular substrate vacuuming and gravel turnover is the best way to both keep your tank clean and keep these pockets from developing in the first place.