Best nutrient reduction strategy for very heavy bioload?

[Belgian Anthias]

So the question arises, what would you use?

When starting up a new system, planning a high bio-load , I would plan a refuge and use it as an algae filter using macroalgae. Certainly not Chaeto as Chaeto can not be used in the food chain. Candidates are Ulva, Gracilaria, Hypnea and others.
For a newbie, I would first learn how to manage such a filter. it must be big enough to remove the normal daily overproduction at 1/2 capacity. One has to learn how much feed it needs to grow at 1/2 capacity. For this, the filter is started up disconnected from the system. Once one has control over the growth rate feeding F medium or any other suitable feed medium and learned what is needed to maintain the filter at 1/2 capacity one can connect the filter to the system at a low flow rate maintaining 1/2 capacity by regular feeding. When the bioload increases and nitrate and phosphate build up one just has to increase the flow rate to the refuge and reduce the feed. The growth is harvested always maintaining at least 1/2 capacity and can be used as food, in the aquarium and in the kitchen. This way one is able to balance the nutrient reserve N/P 9/1 or manage the reserve as desired by limiting nitrogen or and phosphorus in the feed, using for the target nutrient modified feed medium.
I know, it is a big effort in the beginning, but it will learn a lot about controlling nutrients and once it is in the fingers one is able to manage the nutrient content as desired very easily.



Such a filter can easily be combined with a good very effictive remineraliztion filter, removing DOC and exporting nitrogen, having nitrate, phosphate, CO2, as an endproduct. It installs fast and relaiable ammonia reduction and a high and adjustable carrying capacity. The algae filter will gladely make use of the produced CO2, nitrate and phosphate. The algae filter can also be used to balance the night and day PH shift. Combining both filters one has the 3 pilars for a balanced carying capacity supported by photo-autotrophic, autotrophic and heterotrophic ammonium reduction. A good nitrifying remineralisation filter uses calcium carbonate as substrate for the growing biofilm. This limits or eliminates negative effects of the nitrification proces on alkalinty. Ca is produced.

If needed the normal nitrogen export rate ( +- 15% nitrate) of a nitrifying remineralisation filter can easily be increased and adjusted to the needs making good use of BADES.

Such a system is able to support a very high bio-load wile maintainig a very low nutrient reserve.

Does such a balanced system need a skimmer?
A skimmer removes part of the organics constantly but very selective, leaving inorganic nutrients behind, creating an unbalance in the availability of buildingmaterials and nutrients and may be responsible for an increasing inorganic nutrient reserve.
( ref: MB CMF De Haes2017-2018)

Happy reefing

 

[Silent]

Here we go with BADES again lol

 

[Belgian Anthias]

BADES is the best and probably the only safe and reliable option for exporting the nitrogen reserve considered not needed. It is for sure the only method available for managing the nitrate content by denitrification, meaning of having full control over the nitrate removal rate. BADES applications can be used to manage the nitrogen availability and the nitrogen source used and can be used to close the nitrogen cycle by removing the daily nitrogen overproduction daily keeping a very low nitrate level,<2ppm.
Adding elemental sulfur to the calcium carbonate substrate of a normal nitrifying aerobic remineralization filter will increase the natural nitrate export capacity of a nitrifying biofilm, estimated to be +- 16% of the by the biofilm produced nitrate to +30%, the export rate is doubled. Using BADES rolls the export capacity can be increased to + 80%.

The only other option is a carbon-based denitrator which must be kept anoxic, as a result of which the removal rate cannot be regulated as desired and adapted to the needs, the flow is limited in the function of the oxygen content and NOT in the function of the nitrate content. Such an anoxic system can remove a lot at a very high nitrate level but will remove very little at a low nitrate level. The influent will always contain the same amount of oxygen. As the risk for sulfate reduction is very high and not avoidable at low nitrate levels such as an anaerobic remineralization filter may turn into a producer of ammonia, produced ammonia is not reduced in anoxic conditions.
A sulfur denitrator managed the same way and kept anoxic, has the same disadvantages and is not suitable for managing the nitrogen content. We do not advise the use of anoxic kept denitrators in life support systems.

The application of BADES does not need anoxic conditions, the removal rate of nitrate can be managed by managing the flow rate in function of the nitrate level.

Other options based on denitrification as a DSB and so-called" porous rock" do have a very low denitrification capacity due to the very low water exchange rate and are not very reliable, pores get clogged easily. Also important, the removal rate and capacity are not manageable at all. One must be aware that heterotrophic denitrification (carbon-based), which is the same as " anaerobic remineralization", also includes DNRA which transforms nitrate back to ammonia. DNRA is linked to the C/N ratio. adding carbohydrates to the water column will increase DNRA. In anoxic circumstances where heterotrophic denitrification may take place sulfate reduction is not avoidable and HS is produced constantly, which is used by autotrophs to produce sulfur or and sulfate wile reducing nitrate to nitrogen gas. This important autotrophic activity, the reduction, and removal of toxic HS, is the process on which BADES Systems are based.

Denitrators do NOT support the carrying capacity, so using one will NOT help for supporting an increasing bio-load.

Other options do not export nitrogen directly.
Most other options only remove nitrogen from the water column and store it in bio-mass till it is used or reused. 85% is reused, growth needs energy, producing CO2, ammonia, and phosphate.

Using a refuge growth can be managed, bio-load harvested, the removal capacity can be estimated or and measured and the harvest can be reused in the food chain.

For most other options the removal rate can NOT be managed, even not be estimated, certainly not the export rate.

If a high bioload is planned, a mixed reef aquarium, one needs a system that is able to grow, the carrying capacity must be able to follow and support the increasing bio-load.

Focussing on battling the messengers, nitrate, and phosphate levels is not a good idea. The messengers are your guides, not the enemy. They do not kill! A high nutrient system should not be linked to a high inorganic nutrient reserve.



High phosphate availability does support coral calcification! This if enough CO3 is available.

Maintaining a high bioload is not very difficult if one takes into account the growth of primary and secondary producers. Mature High nutrient systems may not need additional feeding for a long period of time. Feeding a refuge makes it easy to avoid overfeeding and controlling inorganic nutrient take up.

Important is the carbon cycle as most carbon is released as CO2. Importing a correct amount of carbon is essential to maintain the food chain. This can be done the natural way or by feeding or a mix of both.
The correct supply of carbon is the main factor for managing a ZMAS. It starts with the protein content of the food.
The higher the protein content, the more nitrogen is left over after remineralization.

Using a good aerobic remineralization filter gives you a lot of options, keeps DOC at a safe low level,, and most important for a high nutrient system, provides a manageable and reliable carrying capacity, at all times. The natural denitrification capacity of such a filter can easily be managed and be adjusted if needed.



In a mature high nutrient system, an inorganic nutrient reserve is not needed as long sufficient growth can be maintained. Your experience monitoring and managing growth in the refuge will tell what is going on and what is needed.



Happy reefing