Richard bray

Denitrification
Denitrification occurs when oxygen levels are low, and anaerobic I bacteria break down nitrates into N2O (nitrous oxide) and N2 I (nitrogen gas). This removes plant-soluble nitrogen from the water I and releases hydroxide.
The bacteria that facilitate this process are called facultative heterotrophic bacteria. A facultative organism is one that uses oxygen
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for energy, but can use other sources of energy when there is no other choice.
Heterotrophic bacteria gain organic compounds by consuming other living organisms. All organic material contains carbon, so these bacteria will grow in piles of solids within your system, and anywhere dead leaves or roots may accumulate.
So, facultative heterotrophic bacteria need carbon to survive, and prefer oxygen for metabolism, but if given no other choice, they will metabolize nitrogen.
In layman’s terms, this means that this bacteria like oxygen in order to eat piles of waste and dead plant material. However, if dissolved oxygen is not available, they will break down N03 (nitrate) to consume the nitrogen. Therefore, denitrification only happens in pockets of your system with low oxygen levels and solid waste or plant material.
This will most likely occur in the corners of your grow bed, in the sludge layer of your grow media, and in your filters.
While denitrification sounds harmful, it can be quite useful in moderation. One byproduct of this chemical process is hydroxide, which has the opposite effect of hydronium. Both are hydrogen ions, but hydronium acidifies the water, while hydroxide alkalizes the water.
So in a system where nitrification produces an overabundance of nitrates, and lowers the pH, denitrification can remove the excess nitrates, and balance the pH by raising it. While nitrates are harmless to fish, if the plants cannot remove all the nitrates within a system, algae may begin to grow out of control within your system.
The key to managing nitrification and denitrification is to resist the urge to clean the parts of your system that have a healthy buildup of bacteria, and to keep an eye on water flow and solids buildup to prevent too many pockets of anaerobic bacteria. Your system shoulc circulate the water completely once per hour, and proper aeration will ensure there is plenty of oxygen for bacteria.
Mineralization
Nitrification is the process that turns liquid waste into nitrogen. Mineralization is the process that turns solid waste into the elever other nutrients that plants need to grow:

• Phosphorus
• Potassium
• Calcium
• Magnesium
• Sulfur
• Copper
• Zinc
• Iron
• Manganese
• Molybdenum
• Boron

Fish feces already contain these chemical elements, but they are unable to be absorbed by the plants. Bacteria must break down the
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waste and release the compounds so that the plants are able to use them.
Mineralization can occur in aerobic or anaerobic conditions, although aerobic mineralization is much better for your system. Anaerobic mineralization can have harmful byproducts that disrupt the ecosystem in your grow beds and fish tanks.
As bacteria breaks down solid waste, they also produce ammonia. This can help fuel nitrification if there are strong amounts of nitrifying bacteria. However, if the system is low on dissolved oxygen, ammonia can buildup and harm your fish.
Mineralization will also break down excess fish food, and release those compounds as plant-soluble nutrients. However, fish waste is a much better source of nutrition, so it’s important to try to meet their needs as accurately as possible.