THANK YOU to the people recommending denitrification. I really don't hear about enough on this site. Usually these are dominated by people saying plants will drop it. They will, but not nearly as well as a denitrification reactor (or deep substrate). Sometimes carbon dosing is necessary, sometimes it's not. My tanks don't have nitrate because of my thick substrate and I don't carbon dose.
These bacteria live all over, but they remove nitrate when they are anoxic (no oxygen). So a reactor is just a media-filled chamber with a very slow flow rate so that the bacteria at the beginning of the chamber consume the oxygen, allowing denitrifiers to colonize the rest of it. They also require a carbon source to turn nitrate into nitrogen gas (which gasses off). You may have adequate dissolved carbon in your tank, or you may need to dose a sugar, alcohol, or vinegar to speed the process up. We use molasses at work with our sturgeon, but you should look up vodka dosing in reef tanks for more info. The deep substrate works the same way, allowing water to pass in but oxygen doesn't reach deep into the gravel. You can look up "deep sand beds" for reefs for more info.
Denitrification also buffers your pH. Nitrification will reduce pH as ammonia goes to nitrate, which is why you hear about "old tank syndrome". Denitrification somewhat reverses this process, creating the carbonate lost from nitrification.
Plants could help a little too, but they certainly won't hurt.
At work our denitrifiers typically reduce the nitrate by 90% when it passes through the chamber.
These bacteria live all over, but they remove nitrate when they are anoxic (no oxygen). So a reactor is just a media-filled chamber with a very slow flow rate so that the bacteria at the beginning of the chamber consume the oxygen, allowing denitrifiers to colonize the rest of it. They also require a carbon source to turn nitrate into nitrogen gas (which gasses off). You may have adequate dissolved carbon in your tank, or you may need to dose a sugar, alcohol, or vinegar to speed the process up. We use molasses at work with our sturgeon, but you should look up vodka dosing in reef tanks for more info. The deep substrate works the same way, allowing water to pass in but oxygen doesn't reach deep into the gravel. You can look up "deep sand beds" for reefs for more info.
Denitrification also buffers your pH. Nitrification will reduce pH as ammonia goes to nitrate, which is why you hear about "old tank syndrome". Denitrification somewhat reverses this process, creating the carbonate lost from nitrification.
Plants could help a little too, but they certainly won't hurt.
At work our denitrifiers typically reduce the nitrate by 90% when it passes through the chamber.
