Chlorella Density Chart
Lower a Secchi Stick into your culture until the black and white pattern just disappears. Read the depth. Then use this chart to turn that reading into real numbers: cells per millilitre, and dry weight in grams per litre.
How to read it
- Find your Secchi reading in millimetres along the axis.
- Read across to get cells per mL and dry weight in g/L.
- Shallower reading means denser culture. As the culture greens up, the stick disappears sooner.
What dry weight means
Chlorella is a microalga. Separated from the water and dried, it has a mass we call the dry weight, expressed against the volume of water it was growing in, so grams per litre.
For scale: the open ocean runs about 0.0001 g/L, a coastal algae bloom about 0.1 g/L, and a good laboratory photobioreactor about 1 g/L.
How to measure your culture