Cycling Daphnia Water

Won't the water in a pot (truly only a pot, a 5-liter flower pot, if one must be specific) of daphnia (also includes snails and yeast) cycle like an aquarium? If so, what is standard operating procedure for dealing with the process - how do I establish a functioning biotope? I.e., must I test this water's quality, too? Where is the bacteria going to form (no filter, no plants, no substrate other than daphnia corpses and snail doodoo) and if it forms in the slime at the bottom of the pot, would pouring the water into a new pot and refilling the old start a new cycle in either the new or old pot? How often should I change the water and when I do change the water, will this reset the cycle (i.e., kill whatever may have been functioning before)?

In deference to the fact that I am posting here among the Advanced topics, I beg forgiveness for my ignorance. I comfort myself with the supposition that the fact that I am trying to breed food for my axolotl perhaps elevates me from the level of amateur pet owner. (Please don't comment on that; I am will always be only a pet owner.)

Disregarding the second paragraph, I would thank you so much in advance for information regarding the first.

-Eva

Have you found John's Daphnia culturing article? It is really quite detailed and should answer a lot of questions.

As to your concerns I think that nitrogen cycle really isn't a problem on such a small scale (i.e. tiny animals producing tiny amounts of waste). While ammonia will be produced the scale is small enough where the ammonia only acts to limit reproduction and not kill the animals. Regular partial water changes should be sufficient along with whatever bacteria eventually colonizes the pot surface to deal with ammonia.

Hi Abraham and thank you for taking me seriously.

Yes indeed I am familiar with John's article on culturing daphnia.

I'm still not sure how regular "regular" water changes should be. Shall I treat the pot as an unfiltered aquarium and change water daily, or shall I leave the poor things in peace for awhile and simply include them in the weekly water change?

-Eva

I take everyone seriously :happy:

I think John's article is pretty will tucked away hence why I mentioned it.

You can take all this with a grain of salt because I haven't raised dapnhia. I think it really depends upon how you feed and that situation. If you are still getting the hang of feeding and you put too much green water or other food in you'll have to compensate with more water changes. If feed provided is just enough or a little short than water changes can be stretched out a bit more. I think I would stick with twice weekly or weekly water changes but hopefully someone more experienced will answer.

haha I understand the place from which your answer is coming and accept it as such, and as one giving such answers herself.

Indeed the article is somewhat "tucked away" (as are many of the best); add to that the confusion of scanning the entire www and attempting to absorb its teachings and then add to your search a second language, and you can then picture the vagaries of my remembered information.

I have most certainly "fed" my daphnia water too much, but as yet it does not seem to be a problem - there are just these whitish clumps at the bottom of the pot. They would be easy enough to remove with the old standby turkey baster or small siphon, but this afternoon I just kind of carefully stirred them around a bit (if you can imagine such a thing) in the hope of freeing some edible parts for the daphnia (my goodness are the babies small!).

So far nothing I have ever read has mentioned the temperature of the water for culturing daphnia, so I'm content on that side as long as it doesn't get too hot (or too cold, I guess, but it's summer now).

In any case, I think you have given me my answer: I do not have to change the water out daily, because the bioload is not overly high in the fresh water : bioload ratio. Should I have comprimised that ratio by "overfeeding" or "over-clouding" the water, I can fix this by changing the water (which is of itself a helpful detail). If not and thus in a normal situation, I can change the water basically when I water my plants (practical, that).

I keep reading (in both languages) that daphnia are "pretty undemanding" - they require food and "like" a good supply of oxygen. These two things I can and do provide (as usual for me, possibly in surplus). I just did not think that I could leave them in a pot of water indefinitely, but that may be a residual effect from reading so (too) much in the fora. I always need water for plants, though, so as long as a water change won't hurt the daphnia, we should all be ok.

Again, thank you, Abrahm.

-Eva

Eva,

I suggest you establish several cultures in case a problem arises, but culture each one less intensively (i.e. a bit less food). The more food you give them, the more oxygenation is needed and the greater the chance of problems with water quality.

A 50% water change weekly should be sufficient under normal conditions, unless it gets very hot. However, in my experience Daphnia will tolerate a lot of neglect. My "cultures" are in water butts around the garden and receive no special attention, just sunlight.

Tristan

i find the best food for daphnia is sheep droppings mixed with water .

Hi Tristan,

Thank you, that's a good idea, having more than one culture. I'll start a second pot today.

-Eva

Don't change water, unless you accidently overfed them (if overfeeding is not severe you want need to change water - all you would need is stronger aeration) I had cultures running for few years and never changed water. Now I have cultures over 6 months old (was traveling, so stopped hobby for 2 years) and water goes only one way - into the culture to replace what vaporized.

I read quite a few articles on the net and I am amazed how much myths is in them.

You don't need nitrification bacteria, amonia, nitrites and nitrates are fertilizer for algae, which in turn are food for Daphnia! By often changing water you are slowing down algae growth whats exactly oposite what you would want!

Your jar already is a biotope. All you really could do is to get another 1 litre jar, add water and teaspoon of MiracloGlo or similar ORGANIC fertilizer, add a bit water from outdoor container (to inoculate with algae/Euglena) and put it in sunlight. After it turns green use that water to replace the water vaporised from big jar.
Daphnia culture works different than fish aquarium. In aquarium freefloating algae are beeing filtered of, the algae established on a glass is beeing scraped of, so there is no natural way to use out all the waste produced by fish. In Daphnia culture you want a lot of waste, because you want a lot of algae (and bacteria). Dont worry, it wont overflow from your jar - that waste is beeing converted into algae biomass, which is beeing converted into Dapnia biomass, which is beeing harversted. It is really so simple. The whole trick is to know how much to harvest. Its always better to harvest a bit too much than not enough. If you harvest too much the only outcome might be slowing down on Daphnia production, while if you harvest not enough the result might be crash of culture. Daphnia might starve to death by eating all algae and bacteria available. If water in you culture is clear thats bad - means you Daphnia has not much to eat, on the other hand if you cant see a thing in a culture thats good (in established culture), just take a tea-strainer and swipe it thru water - you'll see how many Daphnia you'll get.

You not only shouldn't change water in your jar - you should "polute" it even more with chicken manure (some people talk about cow or horse dung , I never tried, alwas use chicken manure). For 5 litre jar, about teaspoon of chicken manure every week should be enough. You can stop adding chicken manure when you have around 2-3 cm layer on the bottom. The reason for a teaspoon a week instead of all at once improve conditions gradually and prevent bacterial boom, which could take all the oxygen from water what would kill Daphnia.

What Tristan wisely suggested is a must - you always need a backup. I put few 1 litre jars with a bit of daphnia in few different places around house and garden; add some snails, some Riccia or duckweed, a bit of compost soil, basically every jar is different. All jars maintenence is to replace vaporised water once a month (if I remember). Most of them (if not each) has handful of Daphnia which could be used to restart culture. Each jar becomes balanced ecosystem rich enough to sustain small population of Daphnia without feeding them. They are selfsufficient.

If you have a space for few buckets or garden then let me know and I tell you how to establish maintenance free cultures - all you have to do is to harvest.

I do partial water changes on my daphnia tubs when the water looks very yellowish. I feed them some algae powder, and I think this turns the water yellow over time. I probably change about 20% of the water every 2-4 weeks.

Daphnia require calcium to make their shells - this may come from their food, or it may also come from the water if they have mineral-rich water. I have no clue, of course, how much they need nor how much would be supplied by the typical daphnia foods. But I justify the water changes partly because I want to make sure they don't deplete the calcium.

I didn't mention before, but I found that chicken egg shells work perfectly as a source of calcium. just dry them and crush in fingers before adding to the tank. I use around 1/4 of whole egg shell per 10 liters even if tap water in my area is hard (around 10 GF). I haven't done any research about that, but have a feeling that egg shells are superior to other sources of Calcium (like chalk) as apart of calcium carbonate they contain quite a lot of calcium phosphate which is an excelent fertilizer for algae. Second, and I think more importan reason why they are superior is that they are free and available on a (nearly) daily basis without extra trip do diy supplier

Anyway, if the water in my cultures was a tiny bit harder I could use it to sharpen knives and Daphnia loves it