Brine Shrimp vs Daphnia

[TheChosenOne]

My most recent experiment with the Daphnia and the red root floaters has been my most successful.   I can't strictly attribute this to the red root floaters but I do believe their uptake of nitrates has helped.  Some research revealed that while excess nitrates may not kill daphnia at lower levels, it can reduce their breeding.   In my most recent attempt I have been running two separate colonies one in the original 2.5 gallon container with an airstone and filter media as well as moving many into a very well established 10 gallon tank with a sponge filter. 

I have experienced crashes in both but both each colony lasted much longer than in the past.  I believe the red root floaters may have helped with this. I've also been able to bring both back after crashes with water changes.  I have begun adding equilibrium to my water changes and using R/O water instead of water from my aquarium.  My most recent crash was a around a month ago and the colony is back to a booming level after a water change.  

 

This image is not at all a good representation of the number of daphnia in the tank as I had just switched the light on. But is shows how basic the setup is. 

[TheChosenOne]

Little update.  I've been taking another try at keeping daphnia in the same small-ish container (2.5gal).   I say smallish because I've seen some people keep cultures in mason jars. 

Things I've changed: #1  I've added a small 20w heater, the same heater that i was previously using when I hatch brine shrimp, which is paying for itself now that it's winter.  #2 I've exclusively been using green water as the food source for my daphnia.  This differs from the past when I've used spirulina powder and yeast and sometimes a combination of the 2.  

The results after 3 and a half months:  I believe this is the longest I've been able to keep a successful culture of daphnia going without serious effort.  This supports other advice i've seen about about adding additional organics to the culture when you use powder and/or yeast.  By using green water I seem to be able to not only maintain the culture but avoid crashes between harvesting/water changes.  The nature of this smallish setup makes water changes a challenge without also removing daphnia. And as the current attempt has gone on i have reached the point where due to work my attention to the culture has lessened and I have to admit to not having done any water changes in the last few weeks.  In the past this culture would have been dead already from my lack of care but with less organics going in less build is occurring in the culture (i imagine, I'm not testing the water). 

Summary: Things are going very well with green water. 

additional update i was curious so I tested the culture. No nitrites, no nitrates, GH was off the chart (my water is liquid rock no surprise there) my KH was about 120 -180 according to the co-op test strips and my PH is around 8?  which is much higher than in my main tank and in the green water tank. Curious.  I did a quick search as I instantly wondering if the daphnia waster and/or molting was a reason for the PH shift.   some reason I found https://www.flinnsci.com/api/library/Download/b049dbe22e12461f83e3da6afab121ca seems to support this.   "A large culture of Daphnia is likely to last for several months. Ultimately, metabolic waste will begin to accumulate in the culture and pH changes in the water will adversely affect the viability of the Daphnia population...."   In the days to come I will take a look at my culture and see what quantity of daphnia I am currently maintaining and consider removing most to restart the culture as advised by the above document.  This will be an easy task of simply catching many daphnia out, and rinse and/or wiping down the container and then restarting the culture. 

 

Edited January 14 by TheChosenOne

[TheChosenOne]

I also just discovered yesterday/today that my daphnia are not nearly as adverse to chlorine or dechlorinator as I thought.  In prepping to re-scape my tank i had to clear out my green water tank to temporarily hold my fish while I re-scape the main tank. I also did a water change on the daphnia culture. I ended up putting a bunch of the daphnia and debri that was caught in the net back into the freshly filled 10 gallon.  I originally bought the daphnia after hearing that they were less sensitive to chlorine and it turns out that might be true. I've never tested it as I've never wanted to wipe them out.  But they made it thro the night with no decholor and even after adding dechlor today they seem to be doing fine. Might save me from being concerned with using tank water/RO water all the time.