I have decided a while ago to try my hand at culturing phyto- and zooplankton. It started out as something I thought would be easy and cheap, but I was quite wrong. That being said, I am sure you can make it work for less, but that is not my way.
I will fill out the details of this endeavour as I progress. Below is an event log.
At 14:30 I started my rotifer culture. The old petri dish from the algae disk was cleaned and filled ½ height with culture water (i.e. 1.015 sterilised water).
I took some culture water to add to the resting rotifer vial in order to shake loose and rehydrate the cysts. This was promptly poured back in to the petri dish where I have placed it in the right corner of the phytoplankton culture vessels, where I hope the spill light from the 24W T5 would be sufficient to meet the 2000 lux requirement.
Cell counting yielded approximately 4.6 million cells / ml in the left culture vessel. The rightmost one could not be counted because 99% of all the Nannochloropsis cells are lumped together in small bundles.
At about 14:30 I added several drops of Nannochloropsis from the left vessel to the petri dish as feed for the rotifers. Cannot yet observe any that have hatched.
Relocated the petri dish water with rotifers to a 500ml flat open container with 500ml of newly mixed saltwater. Fed with more Nannochloropsis, just enough to colour the water light green. I do believe I have visually seen one or two hatched rotifers.
Left culture vessel has 7.5 million cells per milliliter, right culture vessel is at 6.7 million cells per milliliter.
Took 500ml from the left culture vessel and fed to tank. Mixed 400ml new culture water and added to left culture vessel. Added some of this Nannochloropsis to the rotifers, and stirred it. Saw many that hatched.
Relocated the rotifer culture to the third 2L vessel, and added 1.5L newly mixed, sterilised water. Added 10 drops or RotiFeast and a little bit of Nannochloropsis. A very slow bubble rate of 2 bubbles per second stirs the water. Light is not intense.
Drained 1.3L of the right culture, and about 1.1L of the left culture of Nannochloropsis to sterilised containers. Refilled with sterile saltwater. Fed about 350mL to the tank. Rest stored in fridge.
Drained 1.5L from left culture vessel, and about 500mL from right culture vessel. Refilled with sterilised salt water with nutrients as the density seemed to have saturated (visual inspection). Rotifer culture is starting to get significantly more dense, however nothing near the required 400 / mL at day 5 as per the manual.
Day 10 of the Rotifer culture and I finally start to see a much denser colony. The population exploded when I started feeding them more heavily. I think I have been overly cautious initially with feeding. Since adding Nannochloropsis fills up the vessel faster than evaporation, I am forced to harvest them.
I have harvested 1/2 of the culture, screened them through a 53µm filter mesh, and fed the concentrated rotifers to the tank. Refilled the culture vessel with newly made saltwater.