modified lung

IDK what they are. Looks like they swim too smoothly to be daphnia but could definitely be something related to daphnia.

Nice. The secret for me was that they needed a lot more food than I expected, specifically protein I suspect. Blackworms can foul their water very fast so they needed more fresh, clean water and oxygen than I expected too. I think the biggest hurdle is finding a way to give them enough of what they need that's worth the time and effort for you. I fed them any sort of vegetable scrap form the kitchen, the end crust slices of wheat bread that no reasonable human wants to eat, and biofilm I grew by letting a small amount of molasses sit in a gallon jar of water for a few weeks. They'll eat fruit too but too much will cause a bacteria bloom which can cause oxygen problems. Or if you're made of money they'll go through a pack if spirulina wafers in no time. And always have backup cultures. I lost most of my worms multiple times the last year I had them because a pump failed, sponge filter clogged, or I didn't have the energy to change enough water. An extra tip... co-culturing daphnids with blackworms works really well. I'm not sure what they're eating but you don't even have to add any extra food to sustain a small population. Or if you want a larger population, feed spirulina powder. The daphnids eat the suspended power and the blackworms eat whatever settles to the bottom.

Thanks, I just have to not over do it.

@Mac Jank Sry, no updates. Back problems kept me on the couch for too long so I gave everything away.

An aspect of growing blackworms I never see talked about is how the amount of slime they produce affects the culture. I've been selling blackworms to a couple local fish stores (sry I'm too lazy to ship). I try to weigh the worms with as little excess water on the scale as possible. This of course is stressful to the worms. Afterward when placed in the bucket for transport, the water turns a yellowish and cloudy. I hooked up an old acrylic tank to my larger outdoor system to see it more clearly. This first picture is 1 day after stressing the worms out. The water was clear before this: It looks to me like the slime, or whatever it is, reduced the amount of oxygen the water can hold. You can see the worms trying to climb the sides of the tank to get closer to the surface which is also what they do if the air pump shuts off. Increasing aeration in this situation doesn't seem to help. I ran a small pump through the tank for a few days to clear out the water. After shutting the pump off, the water became yellow and cloudy again within a day. This next picture was taken today after the pump ran again for 2 days. The water has mostly cleared out and a lot of slime has congealed on the wall of the tank: This could be why blackworm cultures tend to crash so suddenly: population growth -> less available oxygen (or some other factor) -> stress- > slime -> less oxygen -> more stress -> more slime -> less oxygen -> crash. So the secret to maintaining a dense blackworm culture might be to use a lot of water.

I think that's exactly what I have.

I've gone a record amount of time without equipment failure or general laziness killing half my blackworms. The max holding capacity of a 5 gallon bucket with heavy aeration and no feed seems to be about 30 ounces. That amount goes down fast with heavy feeding which they seem to need to multiply at a quick enough rate. I moved most of my worms to a half 55 gal barrel so I can feed more heavily and not worry about water changes as much.

@g.p. the PVC adapters just weight down food I put on top of the towers. The blackworms are now in a half 55 gallon barrel raised off the ground with cinder blocks + the screen cover keeps predators out.

You'll drive yourself insane trying to ID worms like that 😂😂

It looks like an egg to me as well. I thought the opposite though. The head at the top with some moving mouth parts and grey blob butt. I haven't come across anything like it here though.

I've seen leaches eating blackworms for sure. I have a crazy theory leaches might be important for fragmenting the worms—biting them in half—because I've seen some big population growth in a big tank full of mud, no gravel, and lots of leaches. Good find. I had no idea. Something I never see mentioned is how much slime or whatever it is that blackworms release into the water. The slime probably lowers the amount of oxygen the water can hold. It looks like they release even more slime when they're stressed which could be why they suddenly crash so fast and hard, especially if large population size in a small space (or maybe the increased oxygen needed by the growing population) is a stress factor. Both. The PVC is a secondary though. Leaches and planaria stick to surfaces and blackworms don't which is great. So I take my container of blackworm and dump them into a different container. Then I remove all the leaches and planaria sticking to the bottom and sides of the first container. I transfer them between containers every few hours until I stop finding more. I've never been able to remove them all this way so I add the PVC pipe to keep them more under control. Whenever I see a lot on the PVC, I just take it out and spray it down with the garden hose. Omg, that's brilliant. I'm going to do that.

Biofuel producers will add 400ppm ammonia and even higher to grow their greenwater. Just add as much as you're comfortable with keeping in mind that if you're feeding the greenwater to your Moina, the extra ammonia in the greenwater will be added (although diluted) to the Moina culture as well. I don't remember their threshold (I wanna say it's 4ppm) but Moina don't seem terribly sensitive to ammonia. There's a paper somewhere that talks about high K causing more reproduction in Daphnia. I've never done a K test so I have no idea how high mine get or if it can crash everything. I've had adding Seachem Replenish both kill and cause a huge growth spurt over night in different greenwater cultures. Replenish has Ca, Mg, K, Na, and Cl. So too much of something can be bad. i just don't know what that is. I used to think P needed to be at least half of N but I'm not sure that's true anymore. Something I've been noticing is if P is higher or around the same level as N, there's definitely a growth delay when you first start a new culture (maybe a week, give or take). But when P is higher the greenwater seems to die off much, much slower if N runs out which makes keeping your greenwater alive a lot easier. But then there are reports of greenwater having more nutritional value if P is kept low. Idk if it's higher enough where it really matters though especially if more P = easier.

Lol same thing just happened to me.

I had bleached out algae when trying to use water straight from the tap. I'm not sure I've tried dechlorinator with greenwater. Dechlorinator can kill Daphnia so I avoid it. Maybe that's the cause? There's so little chlorine in my tap I just have to let the water sit over night. One thing I figured out is growing greenwater is way more complicated than you'd think. The tank on the left just started recovering from a huge protist contamination that cleared out almost all the microalgae (pic taken January 25th): All the protists died and the microalgae came back (Feb 8th): (Feb 16th): The black line relates to the greenwater concentration: Also try putting some fresh grass from your yard into the culture. Idk why but it seems to kick start greenwater better than most other things. I put ramshorn snails in there sometimes too.

@memorywrangler Weird, I've never seen fluffy white stuff like that in my cultures. It looks like bacteria floc. Any water cloudiness? Not sure where so much bacteria would come from though. Could there be something on or in the paper towel that's feeding the bacteria? I've used coffee filter paper with good results. Try that if you have some. Ammonia is fine. You can go way higher if you can wait for it all to all be used up. That's more potassium than I would expect. Is that all from the Morbloom or is your water high in K? Or maybe I did the math wrong.

Usually when there's a lot of disagreement on a topic like drip vs plop, that's because it all depends. First, I want to say that if whatever you're doing works, then you're doing it right. Really that's all you need to know here. Second, fish are very different between species so it's impossible to generalize ...but I'm going to do it anyway 👍👍. For pH swings, consider the native water of your fish. Fish from soft, low KH, low pH environments are exposed to pH swings regularly and have evolved ways to deal with it. That's why discus breeders can plop their fish in almost straight RO water with no issues. It doesn't matter in their case. Fish from harder, higher KH, higher pH waters don't always handle pH swings as well. But that also depends. The more calcium in the water the less pH swings affect these fish. The GH/KH balance also seems to matter. It's best to have them within a few points of each other. That's assuming your GH is mostly from calcium and your KH mostly from bicarbonates. Also although pH swings can matter, they seem to matter less than KH swings—specifically bicarbonate swings—even more specifically bicarbonate swings downward. That's because when pH goes down, bicarbs are removed from the fish's body. The fish can adapt over time and reabsorb enough bicarbs to prevent prolonged changes in blood pH as their environment's pH goes down. But if the water KH also goes down too fast, then those bicarbs can disappear faster than the fish can reabsorb them and the fish might die after a week or two. Good general rules are if the fish is from a soft water habitat, it doesn't matter, plop and drop. If the fish is from hard water habitat, slow acclimate. But to make things more confusing. It also matters what kind of water the fish was born into which, unless the fish is wild caught, we usually have no way of knowing. So basically just just keep doing whatever has worked for you with your water and your fish source. For shipped fish and CO2, rapid pH a swing happening immediately after opening the bag doesn't really make sense. It's a lot harder to remove gas from water than people think. After opening a shipping bag I'd say the CO2 would take an hour, probably longer, to completely leave. There really won't be a ton of CO2 in the water so there won't be a massive degassing right away like after you open a soda can. Ammonium changing to free ammonia during slow acclimation into higher pH is a concern. Fish from soft, low pH waters usually have had very little exposure to free ammonia so they're usually much more sensitive to exposure. Definitely plop and drop these fish. Harder water fish can usually handle a little more free ammonia but still you want to keep exposure low. A 40-50% change of the shipping water will cut your total ammonia level right away and only raise your pH from 7.0 to 7.3 depending. If there's a crazy high amount of total ammonia in the shipping water and your fish are flapping their gills very fast, it might be better to just plop and drop these fish too. But at this point there might already be some serious gill damage and especially most nano fish probably won't survive the week. Adding Prime can also help. I've met wholesalers that say immediately adding Prime to the shipping water after receiving fish reduced their fish losses by a huge amount. Honestly, shippers SHOULD be fasting their fish for a few days before shipping to prevent ammonia build up but most don't seem to do that anymore. If they did we'd probably see almost zero losses after receiving fish in the mail. But why would shippers bother when they can just blame the customer, am I right? Anyway, almost all my fish are from hard water habitats. I tried plop and drop for about a year and definitely noticed a negative impact on their long term health, stunted growth, shorter life spans. Usually I put new fish in a breeder box and set it to replace all the water within 30 minutes. That's what has worked best for me.

I actually tested this out and a diet of mixed species of microalgae seems to be a little better and also way less effort then keeping and feeding a pure single species of microalgae. Most things need a varied diet so it makes sense. I was growing some small rotifers for a while that couldn't eat anything much larger than a Chlorella cell so I had to keep a pure enough culture on hand. Usually I just let whatever shows up grow but sometimes my cultures get contaminated with a filamentous microalgae that nothing can eat. I think this has happened twice in the last few years. You wouldn't know it unless you have a microscope or your Daphnia/Moina never seem to clear out the water. I can't get rid of this stuff unless I dump my culture and sanitize everything. I keep spirulina powder on hand in case this happens but I wouldn't have to worry about it if I put in effort to keep a more pure culture.

I posted a "how-to" for making the gravel towers on the Instagram account I was coerced into starting. Here it is: There's a short video reel here as well if anyone is interested.

Depends how dense you want your greenwater. I didn't record this but at one time I had a tank of greenwater that didn't get any PK next to one that did. The no PK tank grew fine, it looked like a normal greenwater culture, although it didn't get as dark as the PK tank. After some time a few of my Moina jars died off the day after adding the usual amount of no PK greenwater. Turned out the ammonia in the no PK greenwater tank had built up past 30 ppm if I remember right while the other greenwater tank read almost no ammonia. I'm guessing the greenwater was sustaining itself with P by recycling die off or maybe from the tap water but there wasn't enough to use the extra ammonia I was adding. So you can definitely get away with not using PK. But you'd be growing a less dense culture (which might suite your needs just fine) and you might have to watch the ammonia level. Tank water? Or are you seeding the green water cultures from prior batches? I seed from prior batches now but my original greenwater was from tank water in a jar with ramshorn snails. I had to sanitize the culture tank and run the water through a fine filter sock to keep the protists, rotifers, and seed shrimp out.

That's also my experience.

Hundreds of scuds can live in an ACO coarse sponge filter. Every so often a couple will dart out into the open. For a year or two I had about 8 rosey red minnows in a 20 long that were only fed this way.

@memorywrangler That's right.

Daphnia do this for sure. I'm guessing Moina does it too. They actually do better in low light. I'm guessing your success here is from the light creating a self sustaining food source and better water quality. There's probably a limit how much you can grow this way but maybe that's all you need. If it works, it works. I've been using these two products to grow greenwater. Together they cost about $15 and they'll last for years: I usually add 1 mL of the ammonia and 0.25 mL of the PK fert per gallon of water at a time which makes about 5 ppm of NH3 and PO4. I do that a few times until the greenwater gets nice and dark. I test for ammonia to make sure it's mostly gone before adding some Moina. Then I start a new batch of greenwater at about this time. I've done this in anything from 1 quart jars to 5 gallon tanks.

The molasses basically causes a bacteria bloom which is quick easy food for Daphnia. They can't live on eating bacteria alone though so you need to supplement with greenwater or something else. It's not very sustainable in the long term either. It really only works if you're doing batch cultures where you want to grow the number of Daphnia in a jar quickly and then feed most of them to your fish right away.

If by polyculture you mean I don't try to control what kind of microalgae shows up, then yes.