Ozone in moderation can be very beneficial in a RAS for fine particulate removal. It removes fine and colloidal particles by micro flocculation which then enables removal by mechanical filtration. IAA uses as standard, 40 micron drum filters, which in collaboration with ozonation is very effective in fine particle removal. The water in a RAS is often discolored by the biological processes in the MBBR, and even though the effect of this is of little importance to the fish, some clients have a desire to remedy this effect. Ozone and fine filtration does exactly that. Read more under "Clear water"