Thanks for the interesting bits of info and experiences.
The ciliates I have now seem to be rather tough and easy to maintain. Yesterday I filtered out debris and rotifers (if any) from a small subculture that I had been maintaining through a 53mic screen. diluted the filtered culture by 50% with new water and added more
IA. Within hours, you could see the concentrated swirls of ciliates in the container. This culture is maintained without aeration and salinity was rather high at 1.031.
I also have another culture that is aerated, and doing well. Salinity in this culture is also 1.030, so maybe they do better at higher salinities.
Under the microscope, they can be seen to be greenish, thus they are most likely ingesting and living off the
IA.
Today I checked another 2 buckets and they too are over run with this ciliate. Pretty much no rotifer looking things left in them. I was able to look at them and compare with a rotifer in one of the samples - these ciliates are small! Looks like you could easily fit 2 of them into the lorica opening of my SS rotifer!

So, chances they will be in the 20 mic range....
....wondering if a 26 micron screen would even be able to screen them out!!
I intend to see if I can keep them going and in pure culture....and then to try them on my
Priolepis nocturna larvae 