Algal Dry Weight and its importance in feeding
Dry weight is the weight of the product the water removed. Reed Mariculture measures dry weight in our microalgae products by placing 100 grams of algal concentrate into an 80 °C drying oven and heating until a stable weight is reached. The weight of the residue is then used to calculate the dry weight. For Nanno 3600, 100 grams of concentrate will yield 18 grams of dry residue, hence it is an 18% dry weight product.
The aquaculture community has long known that cell counts are a very poor method of quantifying algae when they are used for feeding other organisms, because the size and weight of the algae cells vary depending on the culture conditions. For example, the diameter of TW ranges between 4 and 20 micrometers, depending on culture conditions. If you were to feed 100,000 cells at 4 µm vs. 100,000 cells at 20 µm, the biomass difference would be roughly 125 X (4 x 4 x 4 = 64; 20 x 20 x 20 = 8000; 8000/64 = 125), so your animals are getting either far too much, or far too little food.
While it is known that cells counts are a poor measurement, that is often the only measurement that has been available to those growing live algae because the biomass densities of live algae cultures are so small that they cannot be easily measured. However, the introduction of microalgae concentrates has changed the situation, and now feeding your target animals can be done accurately and consistently.