Maintaining O levels and CO2 levels
A few random questions, please, as I'm thinking of doing fixed CO2 and the oxygen levels concern me.
If I inject CO2, how can I maintain oxygen without disturbing the surface (or injecting air) and wasting the CO2?
Should I be concerned about activity like cycling or algae outbreaks, that the oxygen doesn't get depleted?
Will an airstone in a NPT maintain both (relatively) constant O and CO2 levels?
How can I measure oxygen levels without waiting for the fish to visibly suffer?