These are the best videos I could get that give you a clear sense of scale and the relative sizes of the three species I believe to be Moina macrocopa, the smaller Moina micrura and Ceriodaphnia dubia.
You should see the state of my large master culture, the entire bottom is covered in algae, snail poo, a few leaves and other detritus and I rarely ever siphon much of it off when I perform a water change - occasionally I take a leaf out and let my shrimp clean all the algae off. Once I've drained out about half the water I replace it with old water from my aquarium. My tap water is naturally very soft when it goes into the aquarium but I'm not sure what the water chemistry is like by the time it comes out, there's nothing in there that would make it particularly hard though. When I first set up the culture I added a tiny amount of crushed cuttlebone but mostly for the ramshorns that are in there. It may well be the case that a 'mature' culture with a lot of algae has a sort of buffering capacity not just in terms of harbouring infusoria as a food source but also in processing at least some of the waste produced by the moina and excess food breaking down.So I've changed my lights over to a 32W aquarium LED light (a Fluval Plant 3.0 I had spare in the garage). I can't say whether its increased production any, but the Moina seem to hang higher in the water column. I've also increased the bubble rate from the airpump a little and the additional circulation seems to assist in keeping the yeast mixture suspended.
I think its fair to say the production rate isn't very consistent though. I've not noticed a significant 'crash', in population, but increases in population after removing a batch for feeding seem to be taking longer to bounce back.
I did a large (80% ish) water change at the weekend, and that seemed to create a sudden jump in the population in the couple of days afterwards. I'm hoping that once I start culturing the Chlorella @louis_last from your sample, I might be able to keep the population more stable, as I'm wondering if the build up of detritus from the yeast/dried chlorella overtime is lowering survival rates. Hopefully with the live Chlorella I won't get the same contamination of the water between water changes.
A couple of questions:
1. I'm currently still using RO water (with a little potassium carbonate) for the water changes, as I did when hatching the eggs. Do you use tap water in yours @louis_last? If so, how hard is it? I'd like to try transitioning to tap water, as it would be much more convenient, but my tap water is fairly hard - and I can't find any references to whether Moina will continue to produce in hard water.
I've been using cheap bottled water from coop. Now I'm using 5L bottles. I don't think there would be any problem using tap water but if you use prime or any other dechlorinator I'd also let it stand for a day or two because I think these could potentially interact with the fertilisers in some way.2. Similarly with the Chlorella, do you use tap water for that?
I haven't tried using dry salts although there are some videos on youtube with recipes for exactly that, what you'll find is that some of them also recommend adding molasses which is present in the fishmix. This is because the chlorella can use the sugars present as an energy source as well as light and in theory allows it to actively grow during periods of darkness, I understand this is called a 'mixotrophic' culture. You can also add glucose powder and in theory even grow Chlorella in darkness although it won't be green.3. Also on the Chlorella - I have bought a bottle of the BioBizz fish mix stuff (which stinks incidentally lol) you have linked to in the first post, but have you ever tried fertilising it with inorganic dry salts? Is there a specific reason for going with the BioBizz organic fertilizer?
It is usual to have snails in the culture <"to act as tank janitors">.as I'm wondering if the build up of detritus from the yeast/dried chlorella overtime is lowering survival rates.
Hard is fine.but my tap water is fairly hard - and I can't find any references to whether Moina will continue to produce in hard water.
Moina cultures, however, routinely reach densities of 19,000 individuals per gallon (5,000/L) and are, therefore, better adapted for intensive culture.
Hi all,
It is usual to have snails in the culture <"to act as tank janitors">.
Hard is fine.
cheers Darrel
You should see the state of my large master culture, the entire bottom is covered in algae, snail poo, a few leaves and other detritus and I rarely ever siphon much of it off when I perform a water change - occasionally I take a leaf out and let my shrimp clean all the algae off.
That would be my guess. I used to use a mix of tap water and rain water for mine.Is RO/rainwater just required for the egg hatching then? I did wonder if the adult Moina might need minerals from the water column for development/moulting, that the RO water might not be providing - is that likely?
Yes, you can just leave it. It is all fairly inert after it has been through the snails. When you start a new culture I'd actually transfer a bit of mulm to the new vessel.To be fair the snails appear to generate more waste than they actually clean up. Would I be better leaving all this in the base of the tank then, rather than hoovering it up at the water change?
The composition of inorganic fertilizers 3:3:1 produces the highest population density of 2,348 × 104 cells·mL-1 at day of 9.7. The composition of inorganic fertilizers 3:3:1 generates the highest growth rate of 25.9 %/day.
Beech leaves but not too many as a lot of tannin in the water slows reproduction. With some daphnids you get larger, longer lived individuals but with smaller brood sizes if there is too much tannin in the water.Post a picture of it up, it would be a useful reference. What leaves do you add?
I don't heat mine at all, they stay at a pretty steady 22c. It would be really interesting to see a side by side comparison of two bottles with the fish mix and inorganic salts. I have some garden fert pellets that I think are about that ratio, I'm going to go dig them out and set up a side by side in two 5L bottles under LEDs right now. I got the 6-1 N-P ratio I mentioned from the parosphromenus project.I found a paper here on culturing Chlorella using inorganic ferts:
So they found a ratio of 3:3:1 (N:K presumably) produced the best results. They used urea, but I assume I could substitute with KNO3.
One other interesting point was that they quote the ideal temperature range for Chlorella growth as 26-31 degrees C. I assume you don't heat your culture bottle @louis_last?
Post a picture of it up, it would be a useful reference. What leaves do you add?
I've had some <"emoticon smiley issues as well">. "3" : N will be nitrogen, the "3" : P maybe phosphorus (P) <"but it may be P2O5">, and the "1" might be K but it might be K2O.So they found a ratio of 3:3:1 (N:K presumably) produced the best results.
You would need another nitrogen source to get the 3:3:1 ratio, so either ammonium nitrate (NH4NO3) or urea (CO(NH₂)₂.). Personally I'd just go down the <"Miracle Gro"> route.They used urea, but I assume I could substitute with KNO3.
And a video to try and give you some sense of the population density it runs at. I've been harvesting a lot recently because I'm also feeding newt larvae as well as my fish.
This is mine - it’s really hard to film them on the phone, the detail isn’t good enough to pick up all the tiny babies in amongst all the dots that are actually visible, and the camera struggles to focus:
The bottom of the tank is getting there now! I'm really pretty sure you have a different species that is slightly smaller than what is in the master culture I've shown you here. I think the intermediate sized ones, between my M. macrocopa and the C. dubia, that I recently aquired and believe to be M. micrura, are what you've got here and what I sent to Miranda B with her Chlorella starter. I sent you the C. dubia but if at some point you want some of the larger species to mess around with I'll fire some at you too.