Hi,

I personally gave up on fighting protozoa, but later I came across some suggestions. I post them below. I hope you find it useful.

Best, Nikola

Article The effect of ciliate contamination in mass cultures of the ...

https://onlinelibrary.wiley.com/doi/pdf/10.1002/9780470995143.app1

@Nikola Z. Grujic Thank you for sharing. I will try them.

Hi Nikola & Arthi,

I've never tried it before (I also gave up with microzoo...), but you could attract them with a flashlight, most of ciliates or nanoflagellates (motile protozoans I mean) are phototactics. However, your rotifers may be phototactic as well... Do they are free living in the culture or fixed on a substrate? If they are fixed they won't move (I suppose), if not you need to used sieve.