Splitting rotifer culture

[lobsterotomy]

I've got a rotifer culture going, and the bubbles are starting to cause a froth/foam at the surface - I assume this is a sign that I have to change the culture water. What's the best way of going about this?

Do I strain out some rots and add them to fresh sterilized SW and feed?
Or can I just split the cultures as they are and add new phyto?

Also, should I turn off the aeration for a few mintues to let some of the crud settle before decanting some of the culture, or should I just sieve it right away?

 

[GreshamH]

That is indicative of poor water quality. IMO you should harvest 30% or more of your culture daily to keep it young and producing. This gets out the water and keeps the culture nice and strong. Older rotifers don't produce eggs.

I mix up the culture prior to sieving and use a 250µm screen prior to my 53µm screen. This really helps keep the large chunks of debris out.

It also sounds like you are not tackling the ammonia?

What are you feeding them?

 

[lobsterotomy]

I'm just feeding live phyto (Nanno) which I'm culturing at home also - the phyto is doing well so far.

Is there something household I can use to sieve the rotifer culture for now? I can get fine filter screens tomorrow (20/40um, after I use them in the lab - they'd become garbage anyways), but for now is there anything else that would be suitable?

Also, can they be split every 2nd or 3rd day, or even more. If I'm just maintaining them until I actualy need to expand the population to feed larvae, can I get away with splitting them less often?

 

[cabrego]

I'm just feeding live phyto (Nanno) which I'm culturing at home also - the phyto is doing well so far.

Is there something household I can use to sieve the rotifer culture for now? I can get fine filter screens tomorrow (20/40um, after I use them in the lab - they'd become garbage anyways), but for now is there anything else that would be suitable?

Also, can they be split every 2nd or 3rd day, or even more. If I'm just maintaining them until I actualy need to expand the population to feed larvae, can I get away with splitting them less often?

how long has your culture been running? what kind of air stone are you using? It is usually recommended to not use an air stone and use a simple rigid line because the air stone causes a skimming effect. I am not sure if this is what you are observing. If you have large debris you could use a brine shrimp net if you have one, that should have holes large enough to let rotifers slip by.

As far as splitting them, you can start a small culture from must a few rotifers if done correctly. It just depends on what kind of rotifer demand you have and what kind of rotifer density you are working with have. In theory you could split them in half every day for the rest of your life.

 

[lobsterotomy]

Not using an airstone - reading through various culturing threads they all make mention not to do so - I just have rigid airline tubing in there to reach the bottom of my cutures (in 2L pop bottles).

I'm not really concerned about whether or not I can split them everyday - I want to know if it would be ok to just split them every 3 or 4 days until I need them (ie when I have larvae) at which time, I'd go back to every day splitting.