A few months ago I began experimenting with Moina to find a culture method that will eliminate crashes while being very little work to maintain. Culture crashes are typically caused from deteriorating water quality usually from overfeeding, but also from a population growing much larger than the culture can handle. This problem can easily be fixed with filtration. But we need the right type of filtration, something that will not remove the food and will not remove our Daphnia/Moina.
As long as we do not use mechanical filtration and only biological we will not significantly filter out the Daphnia/Moina food. I strongly recommend using a trickle/wet dry filter. Trickle filters will significantly boost biological filtration in a much smaller size, while providing massive aeration. Oxygen/aeration is going to be very important since our cultures will be very dense and produce a lot of waste.
As for keeping the Daphnia/Moina out of your filter simply cover your filter intake or pump in a 200 micron or less media bag (the bags used for carbon/GFO/purigen). Add a roll of canvas mesh or similar inside the bag to keep it from collapsing on to the filter intake. You will need to add snails to the culture to keep the mesh bag clean of debris. With snails there is no need to ever clean the bag.
I have also read papers that high nutrient concentrations (nitrates/phosphates) can negatively effect Daphnia populations. High nutrients signal to the Daphnia that there is little algae (food) in the water. For this I grow some emersed plants at the top of the trickle filter. The plants export a lot of nutrients, but as we all know plants don't remove everything so they don't completely remove the need for water changes. But I believe they significantly reduce the need. I have not done a large water change on my cultures yet, just removing small amounts here and there when I harvest and sometimes to water my plants.
Here is a picture of one of my setups as described above.
You can see the media bag on the left corner which has my pump. The pump is one of the little 90 gph 5W pumps from Amazon. It goes up into the top tray which houses plants then below to a thick layer of aragonite as my biomedia. I chose aragonite for this filter since this culture uses RO water and the aragonite adds Ca/KH that is important for optimal production.
Here is another one of my setups.
Feeding on these cultures is done using a typical fish auto feeder like this one.
I fill it with yeast and set it to feed twice a day. Have the feeder dispense the yeast in an area of higher flow so it mixes well. The amount of yeast you feed is determined by how dense of a culture you want, it is something to experiment with and dial in to your needs. Right now my culture produces way more than I need and it is only 5 gallons. The beauty of this system is overfeeding is not as big of a concern as in traditional filterless cultures. Add an auto top off unit and this culture is almost completely automatic. An airlift tube on a timer can even be added to automatically harvest. Here is a video of my 5G culture, I think the density of my indoor culture rivals that of most outdoor cultures, but it can run year round and hands free.
I am now experimenting with a Daphnia culture that uses a blackworm powered infusoria reactor that I will share soon.
As long as we do not use mechanical filtration and only biological we will not significantly filter out the Daphnia/Moina food. I strongly recommend using a trickle/wet dry filter. Trickle filters will significantly boost biological filtration in a much smaller size, while providing massive aeration. Oxygen/aeration is going to be very important since our cultures will be very dense and produce a lot of waste.
As for keeping the Daphnia/Moina out of your filter simply cover your filter intake or pump in a 200 micron or less media bag (the bags used for carbon/GFO/purigen). Add a roll of canvas mesh or similar inside the bag to keep it from collapsing on to the filter intake. You will need to add snails to the culture to keep the mesh bag clean of debris. With snails there is no need to ever clean the bag.
I have also read papers that high nutrient concentrations (nitrates/phosphates) can negatively effect Daphnia populations. High nutrients signal to the Daphnia that there is little algae (food) in the water. For this I grow some emersed plants at the top of the trickle filter. The plants export a lot of nutrients, but as we all know plants don't remove everything so they don't completely remove the need for water changes. But I believe they significantly reduce the need. I have not done a large water change on my cultures yet, just removing small amounts here and there when I harvest and sometimes to water my plants.
Here is a picture of one of my setups as described above.
You can see the media bag on the left corner which has my pump. The pump is one of the little 90 gph 5W pumps from Amazon. It goes up into the top tray which houses plants then below to a thick layer of aragonite as my biomedia. I chose aragonite for this filter since this culture uses RO water and the aragonite adds Ca/KH that is important for optimal production.
Here is another one of my setups.
Feeding on these cultures is done using a typical fish auto feeder like this one.
I fill it with yeast and set it to feed twice a day. Have the feeder dispense the yeast in an area of higher flow so it mixes well. The amount of yeast you feed is determined by how dense of a culture you want, it is something to experiment with and dial in to your needs. Right now my culture produces way more than I need and it is only 5 gallons. The beauty of this system is overfeeding is not as big of a concern as in traditional filterless cultures. Add an auto top off unit and this culture is almost completely automatic. An airlift tube on a timer can even be added to automatically harvest. Here is a video of my 5G culture, I think the density of my indoor culture rivals that of most outdoor cultures, but it can run year round and hands free.
I am now experimenting with a Daphnia culture that uses a blackworm powered infusoria reactor that I will share soon.
