Reef Juice Live Phytoplankton - Dinoflagellate Control & Reef Nutrition

Something has changed in your tank. The water has a brownish tint in the mornings. A thin film is spreading across the sand bed and up the rockwork. Your corals are less extended than they were. You are running good flow, you have checked your nutrients, and you cannot identify a clear cause. What you are likely looking at is a dinoflagellate bloom, and the reason it has taken hold is almost always the same: a water column too low in biological diversity to compete with it.

Dinoflagellates thrive in nutrient-depleted, biologically sparse conditions. A reef tank without a consistent live phytoplankton input is exactly that environment. Without competing microalgae consuming available nutrients and without a healthy microfauna population applying biological pressure, dinoflagellates encounter very little resistance. They fill the gap the rest of the ecosystem has left empty.

Reef Juice is a four-species live phytoplankton blend of Nannochloropsis, Phaeodactylum tricornutum, Chlorella, and Isochrysis, cultured fresh in Wales and dosed at 1ml per 18 litres daily into a high-flow area of the tank with UV and ozone off for 30 to 60 minutes after dosing. Each species contributes a different particle size and fatty acid profile, feeding fine filter feeders and corals while simultaneously seeding the water column with beneficial microalgae that compete directly with dinoflagellates for dissolved nutrients. Use within three months of delivery, stored refrigerated.

Within weeks of consistent dosing, keepers dealing with dinoflagellate pressure begin to see the biological balance in their tank shift. The film retreats. Copepod numbers increase as their food source becomes reliably available. Corals extend more fully and hold it. The water column feels alive in a way it did not before. Reef Juice is not a chemical treatment and it is not a magic fix, but as part of a sound husbandry approach it addresses the biological root of the problem rather than its symptoms.

Reefphyto has been culturing live phytoplankton in Wales since 2008. Every batch of Reef Juice is produced fresh and dispatched at peak cell density. If you are dealing with a dinoflagellate outbreak and want advice on combining Reef Juice with the rest of your approach, contact us directly. Darren has worked with this problem across dozens of reef systems and responds personally.

If your tank has lost its biological balance, this is where you start rebuilding it.

The Problem Reef Juice Is Designed to Solve

Most reef keepers encounter dinoflagellates at some point. The brown or rust-coloured film that spreads across the sand bed in the morning, retreats slightly under the lights, and returns the following day. The coating on rockwork that healthy tanks do not seem to get. The corals that are slightly less extended than they should be, the fish that seem mildly unsettled, the general sense that something in the tank's biology is off without a clear water chemistry explanation.

Dinoflagellates are a symptom of a biological imbalance rather than a cause. They occupy the space that a more diverse, more populated water column would otherwise fill. In a reef tank with low planktonic diversity, low microfauna density, and a water column that is nutritionally sparse, dinoflagellates encounter little competition for dissolved nutrients and little biological pressure from the organisms that would naturally graze them or outcompete them. They establish, and once established they are resistant to the standard interventions of water changes and nutrient adjustment alone.

The approach that works is biological. Increase the diversity and density of the competing life in the water column, restore the microfauna populations that apply grazing pressure, and give the tank the nutritional inputs at the base of the food chain that allow a more complex, more resilient biology to develop. Reef Juice is designed as the phytoplankton component of that approach.

The Four Species and What They Contribute

Reef Juice contains four live microalgae species, each chosen for a specific nutritional and biological role within the reef ecosystem.

Nannochloropsis (included in blend)

At 2 to 5 microns, Nannochloropsis is the finest species in the blend and one of the most nutritionally significant phytoplankton species in marine aquaculture. Its high EPA content makes it a direct nutritional input for fine filter feeders, sponges, tunicates, and the smallest coral polyps, and it is the primary food source that sustains copepod and rotifer populations in the water column. It also absorbs dissolved inorganic nutrients including nitrate and phosphate as it photosynthesises, contributing to natural nutrient export alongside its feeding role.

Phaeodactylum tricornutum (included in blend)

Phaeodactylum is a diatom with a distinctive elongated cell form and a fatty acid profile rich in EPA. It is one of the most studied marine microalgae species in aquaculture research and is particularly valued for its fucoxanthin content, a carotenoid pigment with antioxidant properties that benefits the animals that consume it. As a diatom, it occupies a different ecological niche from the other species in the blend, competing for dissolved silica as well as nitrogen and phosphorus, broadening the nutrient uptake profile of the blend.

Chlorella (included in blend)

Chlorella is a freshwater-origin green microalgae widely used in both marine and freshwater aquaculture for its dense protein and amino acid content. In a marine reef context it contributes additional nutritional diversity to the blend and provides a food source for a broad range of filter feeding organisms. Its cell wall composition differs from the other species in the blend, offering a different digestibility profile that benefits the full range of filter feeders in a mixed system.

Isochrysis galbana (included in blend)

Isochrysis carries the highest DHA content of any species in the blend. DHA is the omega-3 fatty acid most critical for neurological development and visual function in marine fish and invertebrates. In a reef system, it enriches every filter feeder and zooplankton organism that consumes it, improving the nutritional density delivered to fish and corals at every level above it in the food chain. It is particularly beneficial for keepers of fish species with high DHA requirements and for systems with active larval rearing or juvenile fish programmes.

How Reef Juice Helps Address Dinoflagellate Outbreaks

It is important to be clear about what Reef Juice does and does not do in the context of a dinoflagellate problem. It is not a chemical treatment. It does not directly kill dinoflagellates. What it does is address the biological conditions that allowed dinoflagellates to establish in the first place.

Regular dosing of live phytoplankton introduces competing microalgae that consume the same dissolved nutrients dinoflagellates depend on. As beneficial phytoplankton cells increase in the water column, copepod populations respond by growing, and those copepods apply direct grazing pressure on dinoflagellates and the microbial biofilms associated with them. The water column becomes biologically denser and more diverse, which is inherently less hospitable to dinoflagellate dominance than the sparse, nutrient-available environment they thrive in.

Reef keepers who have successfully resolved dinoflagellate outbreaks consistently report that the biological approach, combining consistent phytoplankton dosing with strong nutrient export, appropriate flow, and time, produces more durable results than nutrient manipulation or blackout treatments alone. Reef Juice provides the phytoplankton component of that strategy.

Used as part of a broader husbandry approach that includes good mechanical filtration, consistent nutrient export through skimming and regular water changes, appropriate flow across all surfaces, and where necessary targeted manual removal of dinoflagellate films, Reef Juice addresses the root biological cause rather than its surface symptoms.

How to Dose Reef Juice

Add 1ml per 18 litres of tank volume daily into a high-flow area of your sump or display tank. Turn off your protein skimmer, UV steriliser, and ozone equipment for 30 to 60 minutes after dosing to allow the live cells to circulate and be consumed before removal. Resume normal operation after this period.

For systems actively dealing with a dinoflagellate problem, dosing consistently every day without interruption gives the competing phytoplankton the best opportunity to establish a presence in the water column. Inconsistent dosing reduces the biological pressure on the dinoflagellate population and slows the recovery process.

Store refrigerated and use within three months of delivery. Shake gently before each use to redistribute settled cells.

Reef Juice Versus the Five-Species Phytoplankton Range

Reefphyto's phytoplankton range includes several products that overlap in application but differ in composition and purpose. Understanding where Reef Juice sits helps you choose correctly.

Reef Juice contains four species including Phaeodactylum tricornutum and Chlorella, which do not appear in the five-species blend. The inclusion of Phaeodactylum in particular gives Reef Juice a specific advantage in dinoflagellate competition scenarios due to its diatom-based nutrient competition profile. The five-species blend, available as 5 Species Phytoplankton, Live Reef Flourish, and Reef Flourish Super Concentrate, covers a broader coral and filter feeder feeding range with Tetraselmis, Pavlova, and Thalassiosira weissflogii providing additional coverage for larger particle feeders and delicate soft corals.

For keepers whose primary concern is broad-spectrum reef nutrition without a specific dinoflagellate issue, the five-species range is the more comprehensive choice. For keepers dealing with dinoflagellates or wanting to maximise biological diversity and nutrient competition in the water column, Reef Juice provides a composition specifically suited to that goal. Many keepers run both, alternating or combining them, to access the full species range across their dosing programme.

Frequently Asked Questions

How long before I see results against dinoflagellates?

The biological approach to dinoflagellate management takes weeks rather than days. Most keepers begin to see a reduction in film density and spread after two to four weeks of consistent daily dosing, combined with good nutrient export and flow. The timeline varies depending on the severity of the outbreak, the existing microfauna population, and how consistently the rest of the husbandry approach is maintained. Patience and consistency are the two most important factors.

Can I use this alongside my copepod programme?

Yes, and this is one of the most beneficial combinations. Regular Reef Juice dosing provides the phytoplankton input that sustains copepod populations in the refugium and display tank. A healthy copepod population in turn applies biological grazing pressure on dinoflagellates. The two approaches reinforce each other directly.

Is this suitable for culturing copepods or rotifers?

The current page notes that Reef Juice is not designed for culturing. For running a dedicated copepod or rotifer culture programme that requires a single-species algae with a consistent, known nutritional profile, Nannochloropsis gaditana or the Nannochloropsis Starter Culture product is the appropriate choice. Reef Juice is designed as a reef tank daily feed rather than a culture maintenance product.

Will it affect my water clarity?

At 1ml per 18 litres, a slight green tint may be visible immediately after dosing. This clears within one to two hours in most systems as the cells are consumed or processed. If clarity does not return within a few hours, reduce the dose slightly.

Can I use this in a nano reef?

Yes. The 1ml per 18 litre dose rate is practical for small systems. A 50-litre nano reef requires approximately 2.8ml per day, which is easy to measure and dose accurately.

Reefphyto - Live Phytoplankton Cultured in Wales Since 2008

Reefphyto has been producing and supplying live phytoplankton to reef keepers, marine fish breeders, and public aquariums across the UK since 2008. Every batch of Reef Juice is cultured fresh at our Wales facility and dispatched at peak cell density. If you are dealing with a dinoflagellate outbreak and want guidance on building a complete biological response strategy, or if you have questions about how Reef Juice fits into your existing feeding programme, contact us directly. Darren responds personally to every enquiry.