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Phytoplankton Storage


Storage & Shelf Life:
There are only two requirements for the proper storage of DT’s Live Marine Phytoplankton.

1. Refrigeration:

Refrigeration should be in a range 32°- 39°F (0°- 4°C).  Storage at warmer temperatures will diminish the nutritional value and cause it to be much more odorous.

The following graph is based on research published in the 2002 Marine Fish and Reef Annual by Fancy Publications


Refrigerated DT’s performed well without much of a decline until 6 months where there was a small, although significant decrease in larval growth. Our “Best if used by” date is based on up to 5 months from the date of harvest.

It is interesting to note that the larvae cultured on DT’s that was left at room temperature for just a few days, had a rapid decline in health and died within 8 days. This was actually worse than the DT’s that was refrigerated for a year.

2. Shaking it up at least weekly:

Phytoplankton settles out of suspension and will die if left packed down on the bottom for too long. Shaking it up vigorously with the bottle inverted is necessary to wash the cells off the bottom. Shake at least once a week to prevent the phytoplankton from packing down. Immediate settling is normal and it does not need to be shaken up every day. Keeping up this maintenance is extremely important for the storage of this product.

Best if used by date:

We only change the date twice a month. Phytoplankton that is harvested from the 1st until the 15th of the month has a best if used by date of the 1st of the 5th month. Phytoplankton that is harvested from the 16th until the end of the month has a best if used by date of the 15th of the 5th month. For example, if harvested between January 1st and the 15th will have a best if used by date of June 1st. If harvested between January 16th and the 31st will have a best if used by date of June 15th.


DT’s Live Marine Phytoplankton does have a noticeable odor and it is normal that the odor is sulfurous. This is due to the fact that a type of sulfide, dimethylsulfide is produced by some phytoplankton and is associated with cryoprotection.

Sulfides produced by living phytoplankton: A small amount of sulfides are produced by phytoplankton that is always in the product. Sulfides are very volatile and they come out of solution and build up in the air within the bottle even at low temperatures. If the phytoplankton is kept at a temperature in the 40’s instead of the 30’s it will have more odor. If it warms up for even a short time, say during shipping, it will have more odor.

We had our product tested throughout its shelf life and beyond. The levels found were very low ranging from 17 to 20 ppm (ppm = parts per million). These levels are very low and were also very consistent from just packaged phytoplankton through phytoplankton that was more than 5 months old (beyond the shelf life). People are extremely sensitive to sulfides, which are detected at the very low levels of 0.5 ppb (parts per billion).

A bottle of DT’s Live Marine Phytoplankton may have a strong odor because dimethylsulfide builds up in the air that has been trapped in the bottle.

The odor from the phytoplankton is most noticeable in the air that is trapped in the bottle, and it builds up over time. That is why a half empty bottle smells more than a full bottle, and a large bottle smells more than a small bottle.  While odor intensity is almost impossible to describe; it is normal for the odor of sulfides to be strong, particularly in DT’s that has been in storage for a while.