Aquarium Water Treatment - An Overview


Aquarium water treatment basically aims to:

  1. Filter out particles of excess food or waste or dust
  2. Remove ammonia by converting it into nitrates or even completing the N cycle by converting the nitrates into N2 gas. This is accomplished in the biofilter where beneficial nitrifying bacteria colonize some kind of media with high surface area.
  3. Trickle filters also remove the CO2 from respiration which affects the pH
  4.  Protein skimmers remove DOC by creating air bubbles in a column and collecting the foam which contains the DOC. Used mostly in marine aquariums
  5. AC filters in Bio-filtration systems remove any medications/metabolites that may have accumulated in the water. Obviously they will also remove the chlorine from the potable water.
  6. UV lamps kill pathogenic bacteria
  7. Air bubbles Oxygenate the water          
  8. Aerobic denitrification or co-respiration the simultaneous use of both oxygen (O2) and nitrate (NO3−) as oxidizing agents, performed by various genera of microorganisms. This process differs from anaerobic denitrification not only in its insensitivity to the presence of oxygen, but also in that it has a higher potential to create the harmful byproduct nitrous oxide.
  9. Nitrogen, acting as an oxidant, is therefore reduced in a succession of four reactions performed by the enzymes nitrate, nitrite, nitric-oxide, and nitrous oxide reductases. The pathway ultimately yields reduced molecular nitrogen (N2), as well as, when the reaction does not reach completion, the intermediate species nitrous oxide (N2O).
  10. To adjust hardness or alkalinity: add hard or alkaline salts or use RO or add distilled water
  11. Natural algae help in filtering out nitrates  

Monitoring Aquarium Water Quality:

  1. Monitoring Ammonia, Nitrites and Nitrates is very important
  2. Monitoring pH is important. High or low pH can stress the Fish
  3. Monitoring hardness and alkalinity is important as low alkalinity can lead to unstable pH
  4. Last but not least the Fish need to breathe hence DO monitoring is very important
  5. You want to watch that BOD coz it will consume DO




Compiled by Rami E. Kremesti M.Sc.