What to Look For in a Microbial Supplement

Every aquarium, every aquaculture system, every planted tank, every sump, every biofilter is a microbial ecosystem. The health, clarity, and biological performance of your water is a direct reflection of the efficiency and composition of the microbial community living within it.

Yet the microbial supplementation market remains one of the most opaque segments in the aquatics industry. Products are sold with vague claims, undisclosed strain lists, and absent or misleading concentration data. If your supplier cannot answer the following questions, you are making a decision without the information you need.

This is not just about choosing a product. It is about understanding what you are adding, how much of it is in the bottle, what each strain does, and how to use it effectively in your particular circumstance. Because probiotics are not a black box. They are precision tools, each one engineered for a specific set of biological tasks.

Probiotics Are Not Just About Nitrate and Phosphate

In the reef and marine keeping world, probiotics have been broadly assumed to be something that helps your filter work better or reduces nitrate and phosphate. That is true, but it is only a fraction of what is happening when you seed a system with the right microbial community.

There are benefits over and above nutrient reduction, some that you can see and some that you cannot see directly but whose effects are measurable and observable as positive, distinct changes before and after using probiotics.

Solid Waste Reduction and Substrate Cleaning

If you want to see the difference for yourself, try this: get your hand into your substrate before dosing. Lift it up and look at the cloud of dust and waste that comes out of it. Let it settle. Dose with Microplex. Wait a couple of weeks and do it again. The difference is dramatic.

Have a look at the inside of your pipes. If you run a canister filter, open it up and look at the waste reserves. How often do you have to clean sponge filters? Before and after using Microplex, the frequency drops. But the nature of the waste changes too. A common piece of feedback is that the waste not only reduces in volume but it clumps together in a mat that you can syphon straight out. It does not dust up. That is the biofilm binding together the leftover humus and organic matter that was otherwise struggling to be broken down further for removal from the system.

In other words, the probiotics help you remove waste by concentrating it, binding it, and making it physically extractable.

Microfloculation and Water Clarity

Probiotics microfloculate particles out of the water column. They bind suspended solids together and sink them. The clarity of the water will increase dramatically. This is not a subtle change. It is one of the first things people notice.

Feeding Action and Behaviour

With improved water clarity and reduced dissolved organics, the feeding action of fish increases dramatically. Fish that were listless or reluctant to feed begin to respond more aggressively to food. This is an observable, measurable change that goes well beyond what people typically associate with probiotics.

A Note on Benchmarking

When using probiotics to address a specific problem, it is very important that you know exactly what you are dealing with and what your benchmark water chemistry is. Measure your parameters before you start. Because everything in the water, the nutrient levels, the chemistry, the organic load, is going to affect one hundred percent how the microbes perform in different circumstances, whether that is reducing waste, outcompeting nuisance algae, or driving a nitrogen cycle. The microbes respond to the environment they are in. Know that environment before you intervene.

If you are sceptical about using probiotics in your RAS system, your aquaponic system, or anywhere else, please contact us and allow us to change your mind. The feedback we are receiving, along with the formulations and research and development we continue to do, consistently returns positive results.

A Note on Aquaculture Systems

For commercial aquaculture facilities running RAS systems, grow-out tanks, hatcheries, and holding facilities, the benefits of properly applied probiotic supplementation extend well beyond water chemistry:

• Reduced biofilm and sludge accumulation in pipes, sumps, and biofilter media
• Cleaner tank walls with slower biofilm regrowth
• Reduced residual ammonia, nitrite, and nitrate levels
• Reduced phosphate and organic solids in the water column
• Reduced alkalinity consumption in some systems, indicating more efficient carbon cycling
• Improved biofilter media maintenance: less clogging, easier cleaning

A common question: If there are already so many bacteria in the system, how is adding more going to make a difference?

The answer is not about total bacterial count. It is about bacterial efficiency. In established systems, the endemic microbial community is often dominated by inefficient, slow-growing strains that have occupied the space through incumbency rather than performance. When you introduce high-efficiency, enzyme-producing probiotic strains at sufficient concentration, you flip the microbiome from one that is merely present to one that is actively and efficiently processing nutrients, producing enzymes, and excluding pathogens.

You will not always see dramatic chemical changes overnight. But you should see reduced ammonia, nitrite, and nitrate residuals, reduced phosphate levels, reduced particulate and solids accumulation, potentially reduced alkalinity consumption, and cleaner system surfaces and equipment overall.

Where Our Range Stands Right Now

Here is what is happening across our microbial range this week, with real results from real systems.

Nitroplex

Nitroplex is our dedicated nitrogen reduction consortium. It contains 16 synergistic cultured strains that form a complete nitrogen-cycling community, and it is designed for all aquatic systems: freshwater and marine, aquaculture biofilters, RAS systems, aquariums, ponds, and hatcheries.

Aerobic Denitrification: A Commercial Game-Changer

Nitroplex operates entirely aerobically. It facilitates the complete nitrogen cycle, from ammonia to nitrite to nitrate and finally to nitrogen gas, all within oxygen-rich water. This is achieved through aerobic denitrification, where strains use nitrate as an electron acceptor even in the presence of oxygen. The implications of this are commercially significant across multiple sectors.

In aquariums, aerobic denitrification enables aggressive nitrate and nutrient control without the need for deep sand beds, remote deep sand beds, plenums, or anoxic chambers. You do not need to engineer anaerobic zones into your system. The bacteria do the work in the water column, in the filter, everywhere that oxygen is present.

In RAS systems, this changes the equation for nitrate management entirely. Traditionally, controlling nitrate in recirculating systems requires either large water exchanges or specialised anaerobic filtration, denitrification reactors that need methanol or another carbon source to drive the process, and careful management of anoxic zones. Nitroplex eliminates all of that. It operates in the existing biofilter, in the water column, in the pipework, anywhere oxygen is present. There is no methanol to dose because Nitroplex feeds off the endogenous organic carbon that is already present in the system. The native organic load that is already there, the waste, the dissolved organics, the detritus, becomes the fuel source. This simultaneously cleans up the system while driving denitrification.

If you are running a RAS system with high nitrate levels and you want to cut down on water exchange, reduce nitrate levels, or optimise your biofilter, or all of the above, Nitroplex is the solution. Simply adding the product and seeding your system with the right microbes can help you control nitrogen across the board, with particular impact on nitrate in systems where it has been a persistent challenge.

Beyond nitrate, Nitroplex also optimises your biofilter for ammonia and nitrite removal. The 16 strains are cultured together, not blended post-fermentation, to replicate the synergy of a mature biofilter. They are pre-adapted to OC-K carbon for immediate functionality. By preventing hydrogen sulphide production, since sulphate-reducing bacteria cannot outcompete the consortium under aerobic conditions, Nitroplex provides a safer, cleaner, and more efficient nitrogen management solution than any anaerobic alternative.

Dinoflagellate Treatment — Ongoing Trials

We are continuing our trials on the application of Nitroplex as part of an integrated approach to outcompete dinoflagellates by consuming the nutrients they rely on. We are documenting which species respond, under what conditions, and at what dosing regimes. For the full breakdown of our dinoflagellate trial data, species profiles, and treatment conditions, see our blog post on dinoflagellates in the reef aquarium.

Microplex

Microplex is our full-spectrum probiotic blend containing every strain in our microbial library. It is suitable for all tanks and aquatic systems for general maintenance. It has been distributed widely this week for a range of applications, and the results continue to validate its versatility:

• Cyanobacteria reduction through competitive exclusion and DOC consumption by heterotrophic strains
• Hair algae and bubble algae reduction by reducing dissolved organic nutrients and outcompeting nuisance algae for trace elements and carbon sources
• Nitrate and phosphate reduction through direct assimilation into microbial biomass and enzymatic hydrolysis of organic particulates
• Organic nutrient and solids reduction as heterotrophic enzyme production breaks down detritus, uneaken food, and organic sediment in gravel beds and substrate layers
• Waste concentration and removal: biofilm binding of organic humus into extractable mats, microfloculation of suspended particles, and dramatically improved water clarity

When to use Microplex: when you need broad-spectrum biological diversity for kickstarting a new system, for general maintenance and top-up dosing, or when no single acute problem dominates. Think of Microplex as the general practitioner. It does everything reasonably well.

When not to use Microplex as a primary treatment: if you have a specific, acute problem such as a phosphate spike, a disease outbreak, or an aquaculture system where you need to preserve a phytoplankton bloom. Microplex contains every strain, but adding more strains to a blend inherently reduces the concentration of each individual strain within that blend. Diversity is valuable for resilience. Targeted concentration is valuable for results.

PMX 8

PMX 8 is our pathogen mitigation probiotic, and it has been producing some of the most significant results we have seen to date. It contains eight microorganisms: Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus velezensis, Paenibacillus polymyxa, Streptomyces hydrogenans, Bdellovibrio bacteriovorus, and Rhodotorula mucilaginosa.

Four-Tier Pathogen Defence System

PMX 8 operates via four synergistic mechanisms, not just competitive exclusion:

1. Chemical Warfare. Streptomyces hydrogenans produces anti-mycobacterial compounds that target the cell wall biosynthesis and metabolic pathways of tough pathogens like Mycobacterium. Bacillus strains produce lipopeptides such as surfactin and iturin that disrupt pathogen cell membranes, achieving seventy percent or greater reduction against Vibrio, Aeromonas, Streptococcus, and others.

2. Biological Predation. Bdellovibrio bacteriovorus is a living predator that physically hunts, enters, and consumes Gram-negative pathogens from the inside, multiplying after each kill. It preys on and completely lyses Gram-negative bacteria including Vibrio parahaemolyticus, Aeromonas veronii, and Edwardsiella tarda.

3. Competitive Exclusion. The six spore-forming Bacillus strains outcompete pathogens for space and nutrients, degrade biofilms, and secrete quorum-quenching compounds that prevent pathogen colonisation.

4. Immune Priming. Rhodotorula mucilaginosa yeast provides astaxanthin and beta-glucans, which upregulate the host's immune markers including lysozyme activity and phagocytosis, enhancing the fish's natural ability to fight off infections.

Freshwater Aquarium Species

PMX 8 has shown dramatic improvements in gut health across freshwater aquarium species. Fish fed PMX 8-supplemented diets and exposed to PMX 8 in the water column demonstrate improved feeding response and feed conversion, enhanced gut microbiome diversity, increased spawning activity and gamete quality, and better overall condition and vitality.

Quarantine and Holding Facilities

This is the headline result. Stores and quarantine facilities that are dosing PMX 8 in both the feed and the water have reported a dramatic reduction in the reliance on formalin, copper, and other chemotherapeutic treatments used to manage disease in incoming or treated fish. The four-tier mechanism means that pathogens are attacked from multiple angles simultaneously, reducing the need for chemical intervention.

Oyster Larvae

We are also seeing promising results with PMX 8, Microplex, and specific single-strain isolates from our Microbe Market in oyster hatchery applications. In trials, these combinations have demonstrated increased larval survival rates, decreased waterborne contaminant and pollutant levels, and improved water quality parameters in larval rearing tanks. These trials are ongoing.

SUB-6

SUB-6 is designed for situations where you want to enhance biological productivity without stripping nutrients from the system. This is a critical distinction.

Phytoplankton Production Ponds

In barramundi phytoplankton ponds, SUB-6 has delivered extraordinary results. This was a direct comparison: ponds running another brand of phytoplankton support probiotic were compared against ponds dosed with SUB-6. The feedback:

But that is not the full story. SUB-6 was also dosed into ponds that were already actively being dosed with the competing product. And the difference it made even in those ponds, where probiotics from another brand and another formulation were already present, was dramatic. Not only did SUB-6 produce better results in ponds where it was the sole probiotic, it enhanced the results out of sight in ponds that already had a competing probiotic running. This tells us something important about the specificity and potency of the strains in SUB-6 and how they interact with the existing microbial community, even one that has already been supplemented.

Silver Perch Farming — Stocking Density Doubled

Feedback from a silver perch farmer in New South Wales this week tells the same story in even starker commercial terms. Since using SUB-6, he has seen ammonia and nitrite drop to undetectable levels, measurable improvements in fish health and growth, and an enhanced phytoplankton bloom. But the most significant result: since deploying SUB-6, he has been able to double his stocking density. Double. In a commercial aquaculture setting, doubling how many fish you can carry in the same infrastructure is a transformational outcome. That is the practical, commercial impact of getting the biology right.

SUB-6 achieves this because it does not strip nitrogen and phosphorus from the water column. Instead, it liberates bound nutrients, including phosphate locked in calcium carbonate substrate and rock, and converts them into bioavailable forms that phytoplankton can immediately utilise. The algae bloom is preserved and enhanced, not outcompeted.

Aquaponics and Planted Aquariums

This same mechanism makes SUB-6 perfectly suited for aquaponic systems and planted aquariums, where the goal is to maximise nutrient availability to plants, not to remove nutrients from the system entirely.

Phosphate Liberation from Rock and Substrate

SUB-6 contains strains with specific remineralisation capabilities. These organisms produce enzymes that can break the mineral bonds in calcium carbonate and other substrates where phosphate and nitrate have become chemically bound.

This is particularly powerful in marine reef systems running organic carbon dosing with OC-K. By combining SUB-6's enzymatic liberation with OC-K's carbon-driven microbial growth, you can accelerate the removal of phosphate and nitrate bound in live rock and substrate, clean rock surfaces, substrate, gravel, pipes, and sump components enzymatically, and reduce the time required to remediate a nutrient-loaded system while maintaining biological filtration capacity.

We are currently trialling SUB-6 in several marine systems specifically for this phosphate liberation application. Results are underway.

OC-K

OC-K is not a probiotic. It is the fuel that powers probiotics. And it feeds far more than just bacteria.

OC-K is our microbial nutrient complex, a carbon source specifically formulated for growing and sustaining microbial populations in aquatic systems. And it is fundamentally different from the carbon dosing products on the market.

• No sugar. No alcohol. Unlike vodka dosing, sugar-based carbon sources, or ethanol-based products, OC-K is completely organically derived.
• Multiple organic carbon forms. OC-K delivers carbon in several different molecular configurations, not a single immediately-available sugar. The bacteria must hydrolyse the carbon matrix before they can use it. They work for their meal.
• Trace nitrogen and phosphorus. The formulation includes precise trace amounts of N and P to immediately rebalance the local nitrogen-to-phosphorus ratio, preventing the carbon-to-nutrient imbalance that causes bacterial dosing to stall.
• Amino acids, vitamins, and minerals. The entire matrix is rich in the co-factors and micronutrients that bacteria need for enzyme production, cell division, and metabolic function.
• Organic matrix structure. Rather than flooding the system with instantly-available dissolved organic carbon, OC-K's particulate structure requires enzymatic processing. The carbon becomes available gradually, in proportion to the microbial population's capacity to process it.

Feeding Your Entire Tank

Because OC-K is a complete organic complex, it does not only feed the bacteria. It feeds your entire tank, from the bottom up. The particulate matrix provides nutrition to rotifers, copepods, Artemia, mysid shrimp, and all of the small micro-crustaceans within the system. It supports plankton. It accelerates the breakdown of organic material within the tank, making the water cleaner. It acts as a food source for filter-feeders including corals, which means you will potentially see polyp extension and increased coral activity as a direct result of dosing it.

You need to think of OC-K as feeding your entire tank, not only because it does, but because we are running closed biological systems. The biology needs to be in peak performance, and it needs food, vitamins, and trace minerals to do that, either periodically or continuously if you are running an organic carbon driven system. OC-K feeds your entire ecosystem from the bottom up. If you take care of the microbes, the microbes take care of the water, and the water takes care of the fish.

We developed and optimised OC-K specifically for growing our own microbes in our own reactors. If it is the best fuel for microbial growth in a controlled industrial setting, it is the best fuel for growing bacteria and feeding the biology in your system.

Microbe Market

Microbe Market is our custom single-strain solution service. When a blended product is not the right tool, targeted single-strain isolates can be selected and combined for your specific application. This is what we have been deploying in oyster hatchery trials, alongside PMX 8 and Microplex, with early success in larval survival and water quality improvement.

Choosing the Right Product

Interested in Trial Results?

If you are an aquaculture facility, hatchery, or retailer curious about how our products perform in real-world commercial settings, we would love to hear from you. We are actively seeking trial partners across a range of system types and scales. Whether you are running a marine recirculating system, a freshwater hatchery, a phytoplankton production facility, or a retail quarantine operation, we would like to demonstrate the difference that properly selected and properly dosed probiotic supplementation can make.

Nitroplex  ·  Microplex  ·  PMX 8  ·  SUB-6  ·  OC-K  ·  Microbe Market