Harvesting is only half the job
As the spirulina culture grows, it takes up nutrients from the growth media it is bathed in. If you just keep harvesting without feeding the culture, the growth media will run out of nutrients. Your culture will not be able to replenish itself and it will end up dying off.  It is not magic. It needs to be fed.
This is the other half of the nutrient equation. The Fast Grow Starter Pack gets your culture established. This pack keeps it producing after every harvest.
What is in the box
- 1 x 1kg packet of pure nutrient salts — enough to produce roughly 3kg of fresh spirulina
- 2 x 50ml vials of chelated iron and trace elements — replaces the iron and micronutrients depleted by harvesting
- 1 x Instruction sheet — exact replenishment ratios after harvest
How it works
When you harvest spirulina, you remove two things: the biomass itself, and the nutrients in the media that the spirulina is bathed in. The media becomes depleted in the key nutrients spirulina needs to grow – Nitrogen, phosphorus, iron, magnesium, calcium, sulfur and trace minerals. Without replenishment, growth slows, colour fades, and the culture eventually crashes.
This formulation replaces exactly what was lost and the culture bounces back within 48 hours.
What happens if you skip it
Some growers try to stretch their media by being stingy with the nutrients. It works for a cycle or two, then the culture turns yellow-green, stops multiplying, and can slowly die off.
Why this formulation
It is based on the Antenna Technologies growth media used in commercial spirulina projects worldwide. Food-grade salts, tested free from heavy metals and contaminants.
Frequently Asked Questions
How is this different from the Starter Nutrient Pack?
The Fast Grow Starter Pack is for establishing a new culture from scratch and is rich in sodium bicarbonate and the nutrients required to create fertile growth conditions. This Post-Harvest Pack is for replenishing an established media after you harvest. You need both for continuous production.
How much does 1kg make?
One kilogram produces roughly 3kg of fresh spirulina over multiple harvest cycles. The exact yield depends on your harvest frequency and working volume.
Do I need a culture to go with this?
Yes. This is nutrients only — no living culture included. You need an established culture already running in your tank.
How often do I use it?
After every harvest. The instruction sheet explains the exact amount based on how much you harvested.
Can I use this as starter nutrients?
No. The ratios and nutrients included are calibrated for replenishment, not establishment. For starting a new culture, use the Fast Grow Starter Pack.
Is this safe?
Yes. All components are food-grade and free from heavy metals and contaminants. Safe for home handling with normal kitchen hygiene.
Keep your culture producing
Add to cart now. Questions before you buy? Email us — we actually answer.
