Anoxic zone creation?

[THX1138CY]

Can filter canisters filled with carbon be cycled 30min on 30min off be used to create an Anoxic zone for the 30 min off time to reduce Nitrates?

 

[mcarroll]

You'd want a stable environment for it, not something that's continuously changing to oxygenated.

Nitrates don't really hurt anything – what's the reason for reducing them? Might have a different recommendation...