Hi all,
Some people say that to get the bacteria going quicker in your filter you need some kind of livestock in the tank, that's why they put the shrimp in straight away, but without overloading the tank with fish too soon before the filters have had time to mature.
Some people have even used Black Molly fry to get things going.
The "sacrificial" fish or shrimp is there to provide ammonia (NH3) via the continual diffusion from its gills, if you already have a source of ammonia (the "Amazonia") you don't need the fish etc.
This is the idea behind "fishless cycling", where you substitute the sacrificial fish for a large slug of ammonium chloride from household cleaner etc. This large initial dose of ammonia means your tank is "cycled" much more quickly.
This has its adherents amongst some people, but I'm definitely not one of them.
Filters breed two types of bacteria, Nitrobacter, and Nitrosoma depending on whether the filter is mechanical (with oxygen - aerobic) or biological (without oxygen - anaerobic) One relies on mechanical filtration and the other on biological filtration. The Ammonia is converted to Nitrite, and de-nitrified or converted into Nitrate by the bacteria, which then is utilised by the plants as fertiliser. Therefore it is not the initial ammonia that feeds the plants.
This isn't quite right, mechanical filtration is just the removal of debris etc from the water column. The finer your mechanical filter is the more it polishes the water.
Biological filtration is the aerobic microbial oxidation of NH3 > NO2 > NO3. You've gone from 3 hydrogens to 3 oxygens, so you've added an acid (acids are H+ ion donors) and you've consumed oxygen. Biological filtration requires a source of carbonates (the bacteria are actually consuming carbon, but using the NH3 as an energy source) and lots of oxygen.
You can potentially anaerobically break down NO3 and outgas inert N2. This is the idea behind deep sand beds and plenums etc. Some filter media claim to support both processes (have a look for the wick test etc on "youtube"). Again having both aerobic and anaerobic processes in your filter is such a bad idea I'm not even going to go there.
Biological filtration is all about oxygen.
Plants take up NH3/NH4+, NO2 and NO3. The original scientific work on the uptake of nitrogen by root hairs actually used Amazon Frogbit (
Limnobium laevigatum) as it model plant. Details in this thread: <
Plants roots....>.
cheers Darrel