At New Dawn, we employ a rigorous sterilization protocol to ensure the integrity and purity of our phytoplankton cultures. This process is consistently applied across all of our cultures.

First, we place our 18" x 24" bag liners into 3-gallon carboys. Using these disposable bag liners helps prevent cross-contamination between cultures, as the carboys can accumulate buildup over time. It is unfortunately a natural byproduct when farming phytoplankton. To sterilize the bag liners, we pour approximately two inches of isopropyl alcohol into each bag and maneuver the bag to ensure the entire liner has been coated. Next, we fill the bags with hot water and let them sit for 2-5 minutes. This helps vaporize the isopropyl alcohol, which could otherwise harm the phytoplankton if left behind.

After the allotted time, we drain the bag liners and thoroughly rinse them with cold water to remove any lingering isopropyl alcohol odor. This step is crucial, as proteins can denature, and cell walls can break at high temperatures. To avoid temperature shock, we ensure the bag is at room temperature before adding the phytoplankton.

Once the carboy is back at room temperature, we add one 16 oz (473 mL) bottle of live phytoplankton. We then prepare a saltwater mixture in a separate container, adjusting the salinity to 1.025 ppt using RODI water and NeoMarine salt. This saltwater is then added to the carboy, typically reaching a volume of approximately 10,000 mL. We leave some headspace to allow for gas exchange and prevent spillage from the aeration.

Next, we add 2 mL of each component from the Fritz 2-part fertilizer. The carboy is then transported to the farm area, placed in a well-lit location (42-watt LED lights) with a 12-hour daily light cycle, and maintained at a temperature of 25°C. Finally, we connect the airline tubing and introduce a gentle, rolling bubble to the surface of the culture. 

This meticulous sterilization process, combined with the controlled growth conditions, allows us to maintain healthy, contamination-free phytoplankton cultures for 1-5 weeks before harvesting.


The process described above serves as a general guideline for establishing new phytoplankton cultures at our facility. We follow a similar approach when cultivating from our live phytoplankton cultures, with a few minor adaptations.

To prepare for a partial harvest, we first sterilize another carboy using the same initial sterilization techniques. This allows us to maintain the existing culture while harvesting a portion of it for our products.

When the phytoplankton are ready for harvest, we only take half of the total culture volume at a time. This approach serves three key purposes:

  1. It enables us to continue cultivating the remaining half of the culture, ensuring uninterrupted production.
  2. It minimizes the risk of the cultures crashing due to the disturbance of a full harvest.
  3. It allows us to provide a steady supply of phytoplankton products to our customers in a timely manner.

To harvest the phytoplankton, we first sterilize a siphon using the same protocols as the bag liners. We then transfer the harvested phytoplankton into sterilized bottles. Thorough sterilization at every step is crucial to prevent any potential cross-contamination during the harvesting process.

Once the harvested bottles are filled, we return to the carboy containing the remaining half of the culture. The remaining half is transferred into the second sterilized carboy mentioned before. We add approximately 10,000 mL of pre-mixed NeoMarine salt solution (prepared to a salinity of 1.025 specific gravity) and 2 mL of each component from the Fritz 2-part fertilizer into the new carboy. The previous liner in the old carboy is removed and the carboy is then moved to a separate section for further use. The new carboy is then transported to the farm area, where it is placed in a well-lit location (using 42-watt LED lights) and provided with 12 hours of illumination per day at a temperature of 25°C. Finally, we connect an airline to the carboy, introducing a gentle, slow-rolling bubble to ensure light aeration of the culture. Depending on the specific phytoplankton strain, the cultures are left to grow for 1 to 5 weeks before the next harvest.
July 05, 2024 — Mitchell Ballou

Leave a comment