You want to grow your own phytoplankton. You understand the value, a continuous, self-sustaining supply of live Nannochloropsis to feed your copepods, rotifers, and reef tank without the ongoing cost of buying it in. What has stopped you so far is not motivation. It is not knowing exactly what you need, where to get it, and whether it will actually work once you have assembled it.

The barrier to starting a home phytoplankton culture is almost always practical rather than technical. The culture vessel, the nutrient solution, the starter culture, the aeration setup, each one is simple in isolation, but sourcing them separately, making sure they are compatible, and knowing you have the right combination before you begin adds enough uncertainty to delay the start indefinitely. Most keepers who want to grow their own phytoplankton never get past that stage.

The Reefphyto Phytoplankton Culture Kit removes that barrier entirely. It contains a 250ml live Nannochloropsis oculata starter culture as a high-density live culture, 100ml of Guillard's f/2 nutrient formula, a 4-litre clear culture container, a 20ml dosing syringe, and an airline suction cup, available with or without an air pump depending on what you already have. Everything needed to set up a productive phytoplankton culture from scratch is in the box. Add light, add saltwater, follow our step-by-step phytoplankton culture guide, and a culture ready for first harvest is typically established within 7 to 10 days.

Within two weeks of opening the kit, a keeper who has never grown phytoplankton before has a productive, self-sustaining Nannochloropsis culture generating enough volume to feed a rotifer culture, sustain a copepod refugium, and dose the reef tank daily. The cost per litre of live phytoplankton drops significantly from the first harvest. The dependency on bought-in stock reduces. And the culture, maintained correctly with regular harvests and f/2 top-ups, continues producing from a single starting point.

Reefphyto has been setting up phytoplankton cultures at every scale from single-bottle hobby setups to large commercial production systems since 2008. The kit is built around what Darren has learned actually works at hobbyist scale, not a compromise assembled from generic components. If you have questions about setup, lighting, or culture management once your kit arrives, contact us directly. Darren responds personally.

Everything you need to stop buying phytoplankton and start growing it, in one box.

If you want to grow your own phytoplankton at home to feed your corals and sustain your live food cultures, the Phytoplankton Culture Kit is the right decision.

Why Grow Your Own Phytoplankton

The economics of growing your own phytoplankton are straightforward. A litre of live Nannochloropsis at retail costs more than a litre produced from a home culture running on f/2 nutrient and electricity. Once a culture is established and running on a regular harvest cycle, the ongoing cost per litre is a fraction of the equivalent bought-in volume. For keepers running a copepod refugium, a rotifer culture, or a reef tank with significant daily phytoplankton requirements, the saving over months of consistent use is meaningful.

But the economics are not the only reason keepers grow their own. A home culture provides phytoplankton on demand, at the density and freshness you control, without depending on delivery schedules or managing stock levels. It is always there. The copepod culture gets fed when it needs feeding, not when the next bottle arrives. The reef tank gets dosed daily without rationing or gaps. The live food programme runs continuously because the supply runs continuously.

What the Kit Contains

The Reefphyto Phytoplankton Culture Kit is designed to contain everything a keeper needs to set up a productive home Nannochloropsis culture from scratch, with no additional sourcing required.

The 250ml live Nannochloropsis oculata starter culture comes from the same production stock as the retail starter culture product, as a high-density live culture. This density is high enough to establish competitive dominance in the new culture vessel quickly, minimising the window of vulnerability during early establishment when contaminating organisms can take hold.

The 100ml Guillard's f/2 nutrient formula provides the nitrogen, phosphorus, trace elements, and vitamins that Nannochloropsis requires for sustained, healthy growth. Properly formulated f/2 nutrient is one of the most important variables in culture performance. Using an underdosed or incorrectly formulated nutrient produces slow, pale cultures that are more vulnerable to contamination and produce lower cell densities at harvest. The f/2 included in this kit is the same formulation used in Reefphyto's own production.

The 4-litre clear culture container allows easy visual monitoring of culture density and health. The transparency means you can see the culture colour at a glance. Pale green indicates the culture needs feeding or is under-lit. Dense dark green indicates a healthy, productive culture approaching harvest density. The container is sized for a first culture that produces enough volume for daily reef tank dosing and live culture feeding without requiring significant space or infrastructure.

The 20ml dosing syringe allows accurate nutrient addition and culture sampling without contaminating the main vessel. The airline suction cup holds the airline securely against the container wall for a tidy, stable setup.

The air pump option, available with a UK plug, airline tubing, and air valve, provides the continuous aeration that keeps Nannochloropsis cells suspended, prevents settling, and supplies the carbon dioxide required for photosynthesis. If you already have a suitable aquarium air pump, the without-pump option provides the same kit minus the pump hardware.

What You Need to Provide

The kit contains the biological and chemical components of the culture setup. Three things are not included because most keepers either already have them or can source them locally without difficulty.

A light source is required. A daylight-spectrum LED strip or fluorescent tube positioned close to the culture vessel and running for 12 to 16 hours per day is sufficient. The closer the light to the culture surface, the faster the growth, up to the point where the outer cells begin to shade the inner cells in very dense cultures. A desk lamp with a daylight bulb positioned 10 to 15 centimetres from the container works well for a 4-litre vessel.

Saltwater at 25 to 35 parts per thousand is required as the culture medium. Synthetic marine salt mix made up with reverse osmosis or dechlorinated water is the most reliable option. If using natural seawater, filter and sterilise it before use to remove competing organisms.

A clean space near a power socket and light source, at room temperature between 18 and 25 degrees Celsius, is the physical requirement. Nannochloropsis is tolerant of temperature variation within this range and does not require a controlled environment.

Setting Up the Culture: Step by Step

Our complete phytoplankton culture guide walks you through every stage in detail, but here is the overview. Sterilise the culture container before first use with a dilute bleach solution, rinse thoroughly with clean water, and allow to dry or rinse with the culture saltwater before filling. Fill with 3.5 litres of prepared saltwater. Add f/2 nutrient at the rate specified in the included guide. Add the 250ml starter culture. Connect the airline to the air pump and place the suction cup to hold the airline against the container wall with the end submerged near the bottom of the vessel. Position under your light source.

The culture will show little visible change in the first 24 to 48 hours as cells adapt to the new environment. Between days three and seven the culture will begin to visibly green up as cell density increases. By days seven to ten under good conditions, the culture should be a dense opaque green indicating it is approaching first harvest density.

To harvest, remove 50 to 70 percent of the culture volume and replace with fresh prepared saltwater and f/2 nutrient at the appropriate rate. The remaining culture will re-establish the harvested volume within three to five days, allowing a regular semi-continuous harvest cycle to begin.

What a Productive Culture Provides

A single 4-litre culture vessel maintained on a regular harvest cycle typically produces two to three litres of dense Nannochloropsis per week under good lighting and consistent f/2 nutrition. This volume is sufficient to feed a rotifer culture continuously, provide daily phytoplankton input to a copepod refugium, and dose a reef tank of up to several hundred litres daily depending on stocking level.

Keepers who need higher production volumes can run multiple vessels from the same starter culture once the first vessel is established, inoculating each new vessel with a portion of the producing culture rather than purchasing additional starters. The initial investment in the kit and ongoing f/2 nutrient is the entirety of the input cost once the culture is running.

How the Culture Kit Relates to the Starter Culture Product

The Phytoplankton Culture Kit and the standalone Nannochloropsis Starter Culture product both contain the same live Nannochloropsis oculata from the same production stock. The difference is what surrounds them.

The starter culture product is for keepers who already have a culture setup, either an existing vessel and nutrient supply or their own sourced equipment, and need only the biological inoculant to begin or restart a culture.

The culture kit is for keepers who are starting from scratch and want everything assembled and compatible in a single order. It is the faster, simpler path from no culture to a productive culture, requiring no additional sourcing decisions before setup can begin.

Frequently Asked Questions

Do I need any experience to use this kit?

No. Nannochloropsis oculata is the most forgiving and best-documented species for home phytoplankton culture, and the included guide covers the setup process step by step. The most common beginner errors, insufficient light, incorrect nutrient dose, and contaminated culture water, are addressed directly in the guide. Darren is also available personally if questions arise during setup or early culture management.

How long does the f/2 nutrient last?

The 100ml of f/2 nutrient included in the kit provides enough nutrient for multiple culture cycles from a single 4-litre vessel. The exact number of harvests depends on the dose rate and the volume replaced at each harvest. For ongoing culture operation after the included nutrient is used, the Reefphyto Phytoplankton Nutrient is available separately in larger volumes.

Can I scale up production from this kit?

Yes. Once the initial 4-litre culture is established and producing consistently, additional culture vessels can be inoculated from the producing culture without purchasing a new starter. Scaling from one vessel to two or three vessels multiplies production volume proportionally using only additional containers, saltwater, and f/2 nutrient.

What if my culture crashes?

Culture crashes are most commonly caused by contamination, nutrient depletion, insufficient light, or temperature shock. Our culture troubleshooting centre covers how to identify and fix each of these with step-by-step guidance. If a crash occurs, the standalone Nannochloropsis Starter Culture is available to restart the culture without needing to replace the full kit. If you cannot identify the cause, contact Darren directly. He is happy to troubleshoot culture issues personally.

Is the kit suitable for feeding rotifers as well as a reef tank?

Yes. Nannochloropsis oculata is the primary food source for Brachionus plicatilis rotifers and a key feed for harpacticoid copepod cultures. A single 4-litre culture vessel producing on a regular harvest cycle can sustain both a rotifer culture and daily reef tank dosing simultaneously in most home setups.

Complete Your Phytoplankton Culture System

The Phytoplankton Culture Kit pairs naturally with our f/2 nutrient for ongoing culture nutrition. For keepers who also culture copepods, our Copepod Feed provides an alternative microalgae blend optimised for Tigriopus californicus, and our Copepod Culture Kit sets up a parallel home copepod supply. For rotifer culturists, our Rotifer Feed Concentrate and Rotifer Culture Kit complete the live food chain. Once your Nannochloropsis culture is producing, it becomes the foundation that feeds everything else in your system.

Reefphyto: Live Phytoplankton Production in Wales Since 2008

Reefphyto has been culturing Nannochloropsis oculata at professional scale in Wales since 2008. The Phytoplankton Culture Kit is built around 18+ years of practical experience in what makes a home phytoplankton culture succeed or fail. If you have questions about setup, culture management, or how to integrate home phytoplankton production into a complete live food programme, contact us directly. Darren responds personally to every enquiry.