Algae Culture Salts and Nutrients
You need both to grow algae, and they do different jobs. This is the single most common point of confusion we get asked about.
Salts are the environment
The salts are the dissolved chemicals that make up the physical environment for algae. To an alga, dissolved salts are what soil is to a land plant. They set the salinity, and ours also carry a heavy carbon buffer that slows pH swings and supplies carbon dioxide for photosynthesis, which is why our media holds a denser culture than plain seawater would.
| Blend | Salinity | Use it for |
|---|---|---|
| Seawater salts | 30 g/L | All marine strains |
| Brainy Briny salts | 40 to 45 g/L | Brine shrimp with algae |
| Spirulina alkali salts | 15 g/L | Spirulina only |
| Freshwater salts | 1 g/L | All freshwater strains |
A small amount of salt in freshwater media looks wrong and is not. Those minerals supply trace elements and the carbon buffer. Distilled water on its own grows almost nothing.
Nutrients are the fertilizer
Nutrients are what the cells build themselves out of: nitrate, phosphate, iron, a handful of trace metals, and vitamins. Most people know fertilizer for a garden. This is the same idea, formulated for algae rather than for land plants.
- Dose at 1 mL per litre of media. About 50 mL for a 5 gallon bucket.
- You are unlikely to overdose it. Toxicity does not start to show until around 30 mL per litre, thirty times the normal dose.
- After harvesting spirulina, replace 1 mL for every litre you took out.
Media is both together
Salts plus nutrients plus chlorine free water is what we call media. If you would rather not measure anything, the Complete Media Kits ship both pre-measured.
If your water turns white, that is carbonate precipitating and nothing is wrong. Stand it undisturbed for 24 hours, pour the clear water off the top, discard the sludge, and carry on.