Nitrogen Cycle, the Myth of “ Nitrate Factories” and Live rock, the courteous Drinker – An Analogy.

I think there is some confusion out there with regards to the use of the term nitrate factory. Following a thread I was hooked on in work today, I thought about this on my way home from work and how I could come up with an analogy to explain the issue, get rid of the myth and help out beginners to understand their filtration a bit better.

Nitrogen Cycle, the Myth of  “ Nitrate Factories”, and Live rock, the courteous Drinker – An Anaology.

I think there is some confusion out there with regards to the use of the term nitrate factory. Following a thread I was hooked on in work today, I thought about this on my way home from work and how I could come up with an analogy to explain the issue, get rid of the myth and help out beginners to understand their filtration a bit better.

Many people have stated that things like bio-rings are “nitrate factories” whilst I understand where this term and view comes from and in some respects it is not totally wrong, it is misleading for beginners.

So, here goes …

The analogy requires some knowledge of bacteria requirements for you to use it in the real world.

Nitrifying bacteria convert ammonia to nitrite and then nitrite to nitrate and require three things,

1)      Food; in this case a nitrogen source which is the waste from your fish etc in the form of ammonia.

2)      They need oxygen

3)      They need a surface to sit on

De-Nitrifying bacteria convert nitrate into nitrogen gas which then leaves the system. They also require three things,

1)      Food; in this case nitrate which is the waste from nitrifying bacteria.

2)      They need low oxygen environment

3)      They need a surface to sit on.

In both cases the surface to sit on can be anything, absolutely anything at all in your tank, filter, glass, pipe, sand, rock, anything. But that surface MUST be in the correct environment, either high or low oxygen depending on the bacteria.

By far the majority of our systems are a high oxygen environment and in most systems there is far more surface than is ever needed to produce enough nitrifying bacteria. Once the system is mature those surfaces will be covered in bacteria but only if they have food. The fact that in a mature system you hardly ever see any ammonia or nitrite means there MUST be enough bacteria and therefore there MUST be enough surface area for all the bacteria to live.

More normally however, low oxygen environments are hard to come by so we must create them. They exist in the lower layers of a Deep sand bed or deep inside your live rock. The fact that we often see levels of nitrate means that there is not enough bacteria to remove it. Therefore one of more of the three things is missing. It can’t be food missing as the food is nitrate and you know that is present, so it must be a lack of surface in the correct environment (low oxygen).

In this analogy I will use people on the site, I don’t wish to cause any offence and don’t think I will but sorry if I use you and you don’t like it but nothing is meant by it. So here are the players….

A Bar – A tank

Beer – Ammonia & Nitrite

Empty pint glass – nitrate

Me (paultys) – I am a nitrifying bacteria

Wayne (who I met today!) also a nitrifying bacteria.

Funky monkey – another nitrifying bacteria

Glass collector – A way of removing nitrates (waterchanges, nitrate tower)

Dishwasher – Denitrifying bacteria.

Passer by – aquarist doing a water test

Beautiful (but somewhat useless) barmaid – fish producing ammonia (beer)

Table – a surface in a high oxygen environment.

Chris Durkin (Bar Manager) – an aquarist!!

A new System….

Chris Durkin, opens a bar. To start with he has no barmaids, therefore no-one to pour beer.

He decides he wants some beautiful barmaids so employs two of them.

They can pour 5 pints an hour ( I told you they were useless) and start pouring away. Very quickly there are lots of pints of beer everywhere and Chris realises he need some customers to start drinking. He buys two tables for his customers to sit at and before long, Paul walks into the pub and sits at the table, he can drink 10 pints an hour (he is hardcore) but if the beer runs dry, he will go to a better pub. Despite drinking away, there remains beer on the bar as Paul can only just keep up with the barmaids  and there was plenty on the bar when he arrived.

Wayne is passing by and sees an empty table and lots of beer, so he sits down and starts drinking 10 pints an hour. Very quickly, the excess beer on the bar is gone, Paul is drinking all the beer the barmaids can produce and so Wayne thinks, this is a crap bar and goes to Yate’s instead (private joke!!)

All this beer drinking has caused a lot of empty glasses so Chris employs a glass collector to clear them away. The glass collector can now clean 10 pints an hour, he can keep up with what Paul is drinking, but cant get on top of all the empty glasses that were there when he first arrived.

To help him, Chris brings in another glass collector, between them they quickly clear the backlog and then, as there are not enough empty glasses being produced Chris sacks one of the glass collectors.

A passer by looks into the pub, he does not see any full pints of beer because Paul is drinking them as fast as the useless barmaids can pour them, and he does not see any empty glasses as the glass collector is cleaning them as soon as Paul has drunk them.

The pub ticks over, Paul keeps drinking, the barmaids keep pouring, and the glass collector keeps cleaning.

The Nitrate Factory Myth and More fish.

Ok many people believe that bio-balls are nitrate factories or in some way produce excessive nitrates (more than live rock) so lets look at it.

Chris decides that he wants more people in his pub, so he buys lots more tables. Wayne sees these tables and decides to give the pub another go. Funky monkey also sees these tables and he comes and sits downs.  However, they are soon disappointed to find that there is still only enough beer for Paul, Wayne tells funky monkey that Yates is much better so they both leave.

Chris thinks to himself hmmmm the tables on their own have not brought in more people. (see my point here, filters of any kind any type cannot, on their own, produce more bacteria and hence more nitrate, they cannot be nitrate factories).

Chirs realises he need more beautiful barmaids so he employer two more, Funky monkey returns and is happy to find plenty of beer so sits at his table and starts drinking. Chris is happy, he has barmaids and people in his pub and they are drinking. But before long he has another problem, all this extra drinking is causing more and more empty glasses. The passer buys looks in, he cant see any full pints but there are empty glasses everywhere!!

This is where the nitrate factory myth comes in; Chris has more tables,  and is producing more beer but has not got more glass collectors. Both the tables and the beer are needed  to bring in drinkers and end up with empty glasses. It is not the fault of the table alone, on their own the tables, even if they were somehow bigger and better tables do nothing.  Just putting in more tables cannot produce more empty glasses.

To solve the problem Chris employs one more  glass collector who manages to clear most of the glasses but never quite keeps the pub totally clean and there are always some glasses on the tables. When the passer by looks in, he thinks, well its not too bad, but if could be cleaner. (this is the situation if you have no surfaces in the right environment for denitrifying bacteria, or dishwashers)

Live Rock, The Courteous Drinker.

Chris has been thinking about his problem. He realises that the best thing would be if Paul, Wayne and Funky monkey cleaned their own glasses. He builds tables and installs a dishwasher  in the middle of each one, the drinkers can then simply wash their own glasses.

Chris thinks wow, this is great,  I have beautiful barmaids pouring beer, I have tables for my drinkers to sit at, and each table has its own dishwasher that they can then put their glasses  in. I don’t need glass collectors anymore.

The passer by is very impressed and all he really sees is the beautiful barmaids!!!

Live rock is the courteous drinker, it does not require waterchanges ( a glass collector) as it has a dishwasher (denitrifying bacteria). Its often thought that by using live rock it is somehow very different to something like bio-balls. But you have not taken away the tables (the aerobic surface), you have just included a dishwasher too! A deep sand bed is the same only better, its like a table with a super-efficient dishwasher!

And in reality there is often not enough live rock so the odd glasscollector is still needed, he just doesn’t work as hard!!

Article Writen by

PaulTys