clayton
Member
I keep reading and hearing confusion about filter mediums and different systems producing too much nitrate (ie bioballs produce more nitrate than other filter mediums, living rock/sand systems do not produce nitrate etc etc) and thought I would help clear some stuff up.
First the nitrogen cycle:
Fish produce ammonia which is toxic, also detritus breaking down will form ammonia. We use biological filtration to convert the ammonia into nitrite and then nitrate which is far less toxic. In a filter the only organisms that do this are bacteria called nitrosomonas and nitrobacter.
Nitrosomenas convert ammonia into nitrite and nitrobacter convert nitrite into nitrate. These bacteria live everywhere in your tank but colonise in huge numbers in your filter. The maturation time is when the bacteria are colonising.
1 unit ammonia = 1 unit nitrite = 1 unit of nitrate. So it is impossible for one type of filter media to produce more nitrate as all the filter media is, is a place for the bacteria to live on.
No other organisms perform this cycle. Living rock will not do it, nor will living sand.
Nitrate is converted back to free nitrogen by anaerobic bacteria (ie must have water with no oxygen in it), no other organisms in you tank (appart from algae which is a different process) convert nitrate into free nitrogen. If you do not set up anaerobic conditions then the levels of nitrate will slowly climb. This is where the plenum system comes in, which is a space under the substrate that has water devoid of oxygen. You will also get anaerobic conditions in the microscopic holes in living rock, porous ceramics and some other filter mediums. The living rock could provide just as good a home for these bacteria if it were dead, it is it's structure that counts.
The advantage of living rock and sand is that less AMMONIA is formed. Tiny worms etc feed on detritus that would otherwise break down into ammonia. Therefore you get less nitrite and nitrate produced by the bacteria in your filter.
A skimmer does a similar thing, it removes organic waste from the water before it has a chance to break down into ammonia and enter the nitrogen cycle.
Tanks which have only living rock and skimmers and no filter to speak of utilise this to the utmost but still have bacteria living on every surface in the tank, performing the nitrogen cycle on the little ammonia that is formed.
I hope this clears a few things up for people as it is the the fundamental basics for healthy tanks. Good luck and happy fish-keeping
First the nitrogen cycle:
Fish produce ammonia which is toxic, also detritus breaking down will form ammonia. We use biological filtration to convert the ammonia into nitrite and then nitrate which is far less toxic. In a filter the only organisms that do this are bacteria called nitrosomonas and nitrobacter.
Nitrosomenas convert ammonia into nitrite and nitrobacter convert nitrite into nitrate. These bacteria live everywhere in your tank but colonise in huge numbers in your filter. The maturation time is when the bacteria are colonising.
1 unit ammonia = 1 unit nitrite = 1 unit of nitrate. So it is impossible for one type of filter media to produce more nitrate as all the filter media is, is a place for the bacteria to live on.
No other organisms perform this cycle. Living rock will not do it, nor will living sand.
Nitrate is converted back to free nitrogen by anaerobic bacteria (ie must have water with no oxygen in it), no other organisms in you tank (appart from algae which is a different process) convert nitrate into free nitrogen. If you do not set up anaerobic conditions then the levels of nitrate will slowly climb. This is where the plenum system comes in, which is a space under the substrate that has water devoid of oxygen. You will also get anaerobic conditions in the microscopic holes in living rock, porous ceramics and some other filter mediums. The living rock could provide just as good a home for these bacteria if it were dead, it is it's structure that counts.
The advantage of living rock and sand is that less AMMONIA is formed. Tiny worms etc feed on detritus that would otherwise break down into ammonia. Therefore you get less nitrite and nitrate produced by the bacteria in your filter.
A skimmer does a similar thing, it removes organic waste from the water before it has a chance to break down into ammonia and enter the nitrogen cycle.
Tanks which have only living rock and skimmers and no filter to speak of utilise this to the utmost but still have bacteria living on every surface in the tank, performing the nitrogen cycle on the little ammonia that is formed.
I hope this clears a few things up for people as it is the the fundamental basics for healthy tanks. Good luck and happy fish-keeping
