Excerpt from “Manual Sturgeon Hatchery” – Daniel TABACARU (second edition)

“3.2.4 Bio-filter Specification

Efficiency of a biological filter is generally dependent on the ratio of the surface film nitrification, temperature, nutrient levels, and of course the level of ammonium, nitrites and nitrates. Also the light is the inhibition factor of nitrifying bacteria. Salinity is tolerated by bio-filter to 5 ppm but the transition from small to large amount of salinity in short time while shock and inhibiting bacteria.

The type of material used for the substrate more precisely culture medium for bacteria is expressed as a function of the type: surface / volume. Common materials for bio-filtration have specific areas of the order of hundreds of meters. Typical uses m2/m3 formula. Each type of biological filter medium has a defined specific surface area (SSA in m2) per unit of volume. Based on this ratio and from the value of the system TAN (Total Ammonium Nitrogen), combined with the rate of nitrification of the filter expressed by the formula (gTAN/m2/day) can be determined by the total area and volume required in the system environment.

Usually they meet nitrification rate values ​​between 0.15 and 1.0 gTAN/m2/zi. The rate of nitrification depends of temperature and water quality, that is the physical and chemical properties of the water. An acidic water with a pH of 5 or alkaline water with a pH of 9, are not suitable for efficient operation of a bio-filter. A water that lacks calcium compounds, poor in calcium and magnesium carbonates is not recommended for such use. Unfortunately the current practice in most of the cases of death biomass (fish) they meet deficiencies in the bio-filter and in most cases it is an improper calculation of bio-filter surface.

One approach is wrong and feel biofiltration as a linear process, when in fact it is dynamic. Nitrifying bacteria that all living organisms have a life cycle that involves cell growth, colonization and ultimately the death of these bacteria. You understand that geometric growth rate of bacterial colonies is extremely slow compared to other species of bacteria. It is known that after processing a gram of ammonium using 4.6 g of oxygen, 7.1 g of alkalinity and only 1.5 g of cell mass just results in the new colony.

Colonization of a bio-filter startup operation is a long and generally requires weeks.

Advanced aquarists know how to make cycling with fish but often prefers to be made ​​without fish in the aquarium. And in aquaculture things are just as here we have a huge economic stake and a high density of biomass.

Since a large part result from breathing ammonia in fish have a large amount of fish system means we have a great source of ammonia. At more than 1.6 mg / l NH4 bacteria “choke ” so the idea of having a large amount of fish in the system are excluded. On the other hand we still have to source sufficient bacterial colony development and especially to go in ” tandem ” with their nourishment from these bacterial cell division.

A delicate balance that requires very precise experience and understanding of the phenomena, the proportions , the mass and balance between inputs and outputs system . A long time 10 to 16 days, the entry will be increased gradually (number of fish, their size, the amount of food) without having other outputs than the exchange of fresh water that will be great for you are in control the NH4 not more then 0.5 mg / l.

Also good mechanical filtration and retention of ample fish feed are welcome. If fish feed several times a day will have a material failures partially absorbed in the intestinal absorption and generate additional organic matter.

This leads to the development of heterotrophic bacteria. Champion of the colonization of our planet they reach 40 million units in a gram of soil and a million copies in every milliliter of water. In the natural environment these bacteria are considered useful because both the diversity and development through their feeding help regenerate the environment.

In our system these bacteria have a limited role in the process of organic matter and convert it mostly in nitrifying ammonium that they will turn away in as little toxic chemical products.

If the biofilter during the start (first 16 days) and you we will have a high level of organic matter in the water because food will cause a given ample development of heterotrophic bacterial mass in biofilter . In this case colonization of nitrifying bacteria will be extremely cumbersome or even impossible.

From experience I can tell you that turn water recirculation system over substrate even without the fish in the water is wrong.

Colonization success of even the best depends on the purity of the material used as a substrate for bacterial growth. Even if bio-balls are commonly used plastic products chemically inert their exposure during storage or transport in air or water can compromise quality. As a precaution fully justified they should be ” stripped ” before it is inserted into the biofilter . This can be done in a washing machine ( small capacity ) or a high-capacity system constructed of a mixer used to mix plasters and adhesives and a large bowl (500 liters) fitted at the bottom with a drainage system . Bio-balls will be agitated 12 hours in hypochlorite solution with a concentration of 14% dissolved in water in a ratio of 1 part NaClO / 200 parts water. Following this bio-balls will be rinsed with clean water until the pH of the washing water will reach the amount of running water. Usually this operation lasts 6 hours and used a volume 20 times the volume bio-balls. To remove any residue of chlorine (if the washing is done with the drinking water supply from network) that may have remained on the surface it will sink and shake in a single unit volume of water and an addition of 10 g / 500 liters sodium thiosulphate , Na2S2O3 .”

If you want to use data and text above to create articles and publish them on another site a Bio-filter Specification you need the approval of the author. This work is protected by Law. 8 of 14 March 1996 on copyright and related rights.

For more information about Bio-filter Specification contact here…