Brine shrimp condenser being rethought

My current setup is sufficient for hatching the nauplii, but I still need labor saving devices and measures to make sure I have more time to devote to other projects.

I have two problems with the current brine shrimp condenser design:

  1. A mesh screen by itself will not allow the hatching membranes and other nauplii sized debris to be rinsed away. A more complicated arrangement is necessary to separate the nauplii from this debris.
  2. The filters used to clear the water are not fine enough to capture the 1-2 micron Nannochloropsis algae particles and SELCO emulsion.

I have been seeking out a retailer to obtain a commercial rinser/condenser from INVE Aquaculture so I can compare the price and capabilities and decide if building my own is still worth it. I would also like to understand the basic design of a commercial rinser (I have seen at least 2 different types) and see if I can get some ideas. For now, this is a critical aspect of reclaiming my time during the day from rinsing and hatching nauplii.

Brine shrimp condensor/rinser first run

This is my first test of the condensor/rinser on approximately 2.5MM nauplii that have been enriched for a day.

After a lot of work and planning, I finally was able to get my hands on the replacement nets for the fish hatcheries and test my brine shrimp condensor/rinser idea. The short summary is it worked, and I was able to save valuable time by having the device rinse my Artemia nauplii while I did other work in the lab. There were some kinks I would like to improve however, because these nets were hand sewn they are all slightly different fit over the frames, which leads to tiny gaps along the edges where the nauplii get caught in. When harvesting, there is some difficulty getting these lines of nauplii out. I could just abandon them as acceptable losses, but I feel like this is a problem that can be solved.

The other kink that may be problematic is the filtering on the condensor/rinser. The water movement is provided by two Penguin 100B biowheel pumps from Marineland that I have laying around. The filter cartridges uses have a mechanical gauze filter over some active carbon. I am not sure this is sufficient to clear the water of all the metabolytes, Nannochloropsis algae particles, SELCO particles, and various waste that is introduced into the tank. The water is slightly cloudy and shows no signs of improvement after several hours in the lab. If these pumps won’t work, I’ll have to think of a different solution.

First test of the hatching station

Although it’s not quite done yet, it’s been useful for hatching and harvesting.

Now that I’m back from my business trip, I had an opportunity to use my hatching station. It has been quite helpful, I feel that the harvesting and rinsing process is much easier and takes less time than before. I use the lights to get the majority of the nauplii out into some Pyrex dishes, then drain the rest of the tank through the sieve to get the rest of the nauplii. Then a pipette is used to transfer the rest of the nauplii heavy liquid through the sieve.

After that, I have all the nauplii in the sieve box, and then I can begin the rinsing process. I just rest the sieve box in a Pyrex dish and pour in 2 cups of saltwater at a time. My current record is using up 2 gallons of saltwater and I was still getting cloudy water. Which leads me to the next project, which is finalizing the replacement nets on the fish breeders for use in the condensor/rinser.

I have been using two hatcheries at a time for hatching, each one holds 1.5L of 25.0 ppt saltwater with 3g equivalent (6g) of EZ-egg decapsulated brine shrimp eggs. I have noticed that it takes only about 12-14 hours for these to hatch, so my schedule has been accelerated:

  1. 12 hours to hatch eggs
  2. 12 hours to develop to instar II
  3. 12 hours of enrichment with Nannochloropsis and SELCO
  4. 12 hours of enrichment with Nannochloropsis and SELCO again
  5. Harvest, rinse, and then feed/freeze

This has been giving me approximately 2 days of live feed (I feed some out immediately after they hatch, and immediately after enrichment) plus the leftovers gives me about 16g of nauplii to freeze. This equates to about 3-4 days of frozen food plus the 2 days of live feed. If I can scale up just a tiny bit more, I can make this a weekly process.

Brine shrimp hatching station built, Jellyfish Art tank fixed

The station is built of plywood and has a power strip with A19 bulb sockets plugged in to provide light. I chose to use some 450 lumen LED bulbs I had lying around but anything will do.

My experience leads me to believe there is merit to using the phototactic response in nauplii for harvesting. A healthy nauplii population will very aggressively move towards light sources, which makes harvesting much easier if there is a way to get the lights underneath the drainage spigots. Since my hatcheries were just a tad bit too low for me to fit a bowl underneath, I realized I could fix both problems.

I built a 24″ x 7.5″ frame out of 2×6 plywood and joined it with 3″ wood screws. The hatcheries rest on top of this, and I have particle board bottom and plastic top to cut. Inside, I have mounted some cheap Belkin power strips to hold some A19 socket to plugin converters. Then I just got some light bulbs I had lying around to plug in. The result is not only the hatcheries are high enough to easily fit any container underneath the drain, but now I can turn on some 450 lumen lights underneath. The resulting light draws the nauplii to the bottom for easy harvesting. Any remainder can be collected in a vessel and dumped into the rinser/condensor tank next to the hatcheries.

As a side note, I found out that something was blocking the air port at the bottom of my Jellyfish Art tank. After hours spent tracing my air hose and checking for leaks and good seal, I finally just unplugged the entire tube from the bottom of the tank. To my immense relief/panic, I noticed not a single drop of water drain out of the tank. I took a needle and pushed in, and something popped out. It looked like the tube was plugged with something solid but I couldn’t tell what it was. Then water started to drain out of the tank. Quickly replacing the hose, I finally got a blast of air and a huge current going. Even my weakest pumps would create huge current, so Portabella is now happily suspended in the center of the tank again. The unsightly algae, Nassarius veliger, and various copepods are no longer congregating at the surface of the water with protein scum.

Brine shrimp condenser update

The prototype is composed of an Aqueon 5 gallon tank with two Marineland Penguin 100B filters and two Hagen fish breeders. I have replaced the fish nets with a 105 micron, 52% open area mesh net. The tank dimensions are such that the overflow from the Penguins should arc into the mesh cubes, rinsing the nauplii.

The prototype brine shrimp tank is in its final stages of development. After reading the culture manuals from the United Nations Food and Agriculture Organization, it is clear this tank takes up the purpose of a rinser and condenser rather than a culture vessel. By providing a high water flow, a filter to remove contaminants, and oxygen, it allows the nauplii to survive and be cleaned without intense manual labor (e.g. I can leave them in the condenser/rinser for an hour). If necessary, they can be left in there for longer, although feeding them to maintain nutritional level is a concern. For starters, I’m going to reuse one of my Aqueon 5 gallon tanks to setup a two mesh-cube arrangement. If it becomes necessary, I can buy a longer Aqueon tank and move up to five mesh-cubes.

I grabbed the wrong spray bottle by accident and frosted the acrylic hatcheries I had by rinsing them in isopropyl alcohol.

This whole project started when I grabbed the wrong spray bottle and hosed down my acrylic hatcheries with isopropyl alcohol. The alcohol acted like a solvent, stripping the binding agent of the acrylic off the surface, and then it deformed ever so slightly giving me the frosted glass opaqueness. Unfortunately this made the hatchery very suspicious to use; I have bits of plastic residue in the hatchery and the lack of transparency makes light difficult to get to the eggs.

Changes in this attempt include a new magnet shape (cross rather than bar) and the addition of the air pump to provide aeration.

As a stop gap measure, I am trying to hatch eggs using my magnetic stirrer again. Although the magnet did make some unfortunate crunching noises, the aeration from the air pump seems to be doing a good job of making sure all the eggs are suspended. The strange part is the magnet is enough to make sure the eggs are suspended, but the aeration ensures they stay out of the magnet’s way. Finally, I suspect part of why the previous attempt didn’t work is that the stir bar doesn’t provide enough oxygen into the water. Perhaps the contact of an air bubble with the eggs is what triggers their hatching.

Baby brine shrimp culture tank plans

I am making plans to turn an Aqueon 33 long tank into a baby brine shrimp culture tank. Maybe not paying sticker price though.

I’ve revised out the idea I had for the baby brine shrimp culture tank (from hereon, to be referred to as the BBSCT). In my Nassarius tank, I’ve been having a cyanobacteria bloom because we love our snails a little too much and obviously overfed them. When there’s food leftover in the tank, it’s a clear sign you are loving your animals too much! That was a good warning sign to me that using biological filtration is going to work, until it doesn’t, and then it’s too much work to fix it again. Mainly I am concerned about another cyanobacteria outbreak because the Chaetomorpha has to come somewhere, and that somewhere always has cyanobacteria samples.

I have some old Marineland Penguin Bio-Wheel filters lying around, which made me revise the plan to primarily use mechanical filtration to keep the BBSCT clean. The size A penguin filters have a kind of gauze filter to catch bits, followed by active carbon and finally the bio-wheel will contain nitrifying bacteria. They are disposable and replaceable, which is helpful in case you have to sterilize and bleach the tank due to an outbreak.

So far my plan is as follows:

After hatching the brine shrimp eggs, they will be dumped into the BBSCT for maturation into instar II phase and then feeding. Any further enrichment will be done the day before in a separate vessel (possibly just a Pyrex dish, with an airline and a drop of SELCO) before immediate feeding. The concept is now to make the keeping of the baby brine shrimp as convenient as possible so that enrichment is not so much of a hassle. I have yet to find a way to store dense amounts of baby brine shrimp past 24 hrs in refrigeration without making gathering them up another chore with the sieve.

UPDATE: After finding the Food Agriculture Organization of the United Nations manuals on Artemia breeding, it turns out this prototype is exactly what they describe as a “rinser/concentrator”. The Artemia nauplii are not stored in it for a long time, but they are rinsed long enough that oxygen deprivation is a concern, hence the filters and water flow. The only other difference is the inversion of the compartments. Based upon photos, it looks like the nauplii typically go into the outer tank, with water trickling into the mesh cube for suction and removal. I’m doing the opposite, with the nauplii being in the mesh cube and the tank circulates the water into my hang-on-back filter.

Prototype brine shrimp culture tank

I am attempting to deal with the hassle of culturing brine shrimp nauplii by using biological filtration, e.g. a sand bed along with macro algae. Assuming the net area works, the next step is to get a much larger tank with a deep sand bed, a protein skimmer, and more macro algae.

I’ve been raising a lot of Artemia nauplii to try to feed the jellyfish. I’m looking for ways to keep the food “fresh” as I’ve noticed that dead nauplii in the refrigerator begin to rot fairly quickly despite the refrigeration. I am assuming this is because the nauplii are so small, even with reduced bacteria growth it doesn’t take much to ruin them. Since nauplii take a relatively long time to culture (72 hours from hatching to enrichment), it’s important to keep them alive as conveniently as possible. Most guides I’ve seen online admit that nauplii are tricky and labor intensive to keep due to their small size and the large amounts of waste their fast metabolisms generate. Commercial operations seem to simply use economies of scale, with huge vats, light based harvesting (you compact the nauplii using bright lights and just siphon them out), and bleach to clean equipment between batches.

My idea is to try to use a biological filter (such as an existing saltwater tank) to filter out all the waste from the nauplii harvesting. I would store the nauplii in multiple mesh storage cubes that are submerged in the larger tank. These mesh cubes are based on fish breeders, in fact I took a frame and had a friend make a replacement bag out of 105 micron opening mesh material. The goal is to eliminate some of the water changes that were necessary for growing, feeding, and enriching the nauplii. I could see the system handling the growing to instar II and feeding stages. All the waste material will be filtering in the tank, and any decaying material will simply be mineralized, and then consumed by the macro algae. Organic waste from the algae will then be exported via protein skimmer. Hatching will still require a specialized vessel, and enriching would still need a separate system as well.

In the end, I will have a large 20+ gallon culture tank that has enough room for a sand bed to hold nitrifying bacteria, Chaetormorpha macro algae, a protein skimmer, and 4 or 5 of these mesh storage cubes. Each cube will hold the nauplii of a 2L hatching cone, or approximately 4g of eggs (or 400,000 to 500,000 nauplii). Each batch is pipelined and fed through the common holding tank; whenever I need to enrich for feeding, I’ll take a mesh cube out, dump it into an enrichment vessel, and then harvest and feed. This potentially eliminates one third of the water changes required, but most importantly it recycles water. I can hatch the nauplii by taking water out of the culture tank, and I can simply harvest the nauplii by draining back into the tank. So long as the total volume is enough not to ammonia spike, the system will absorb and export all the organic waste.

The potential downside to this approach is it’s complicated and you could crash the tank. Once you get an ammonia spike and nuke your harvested nauplii, you would have to hatch new batches and have several days without food. The other thing is if you introduce parasites or undesirables into the tank, it’s possible your nauplii (and their water) will be polluting whatever you feed them too. This is the only reason I think this approach is not used commercially but it would still be viable at home since you have ultimate responsibility over what goes into your tank.