brine shrimp refugium/perpetual plankton producer

[TheFishMan65]

I have the luxury of having seen this in person. It is build in a sun room so three sides are glass. The fourth is steps down from the house. He really has no space above the tank and what little he does have he is using for algae growth.

 

[dave willmore]

Subscribed, I admire your ambition and I really want to see how this project turns out.

Feeding would be simplified if the culture tank were above the DT. You could still have the settling chamber/sump beneath the DT with the culture tank feed pump as a macerator for detritus. I'm thinking a series of 24" laundry tubs with drains to a manifold to the pump.

Since you're welding stands your probably way past the point where my comments are realistic so I have a suggestion for a BBS safe feed pump. You could probably DIY up a water wheel with a low rpm electric motor and some PVC. You'd get a bonus surge with each BBS dump.

You are right that the best place for any refugium should be above the DT so gravity can flow zooplankton to the corals without passing through pumps.

I have a greenhouse room that is 16' high on the north (house) side, but then drops to ground level on the south side so there is not room for several thousand gallons of refugium above the tank.

I will look into your waterwheel thought. I need to pump concentrated BBS about 4 feet from the refugium to the DT. I was thinking of using two or three dosing pumps or micro pumps to do this, as I only need to lift 30 or 40 gallons of BBS per day and the micro pumps that squeeze a silicone tube should not damage the BBS plankton.

Thanks for the waterwheel idea.

 

[skimeister56]

This is a great question xboxdisc, if you follow the goal of keeping plankton alive and deduced that there isn't a lot of water pumped from the sump to the tank. I could use a diaphragm pump, Jabsco makes one for about $300 (model #66000 or something like that). I could also use an impeller pump knowing that it will kill 10 to 20% of the BBS which will be quickly consumed anyway. I don't have a better solution so far, can you think of one?

I would use a diaphragm type pump. We use air powered diaphragm pumps to pump out manholes. You can easily adjust the speed, which should help your survival rate, they will pump almost anything, and the rubber diaphragm does not corrode and is easily replaced.

 

[aninjaatemyshoe]

A food loop is made where brine shrimp consume waste and produce plankters so I hope to greatly reduce or eliminate food, yet still keep planktivores and corals happy.

I think this is the part of the plan that will fall short. If I understand you right, this is how the cycle would work:
-fish poop feeds the adult brine shrimp
-from the energy gained in feeding on fish poop, the adult brine shrimp produce baby brine shrimp
-the baby brine shrimp serve as food for the fish/corals
-from feeding on the baby brine shrimp, the fish generate enough fish poop to keep the cycle self-sustaining.

There is no way that this cycle could be self-sustaining. In each step, a great deal of energy/nutrients is lost. You need to be adding into this system in some way, and not in a minor way at that. You could add to it by way of feeding the fish directly with other food or dosing phyto for the brine shrimp. IMO, it will probably take both methods to keep this system sustaining.

 

[installman]

Wow great idea. Hope it works as well as planned.

 

[herring_fish]

PLEASE! PLEASE! PLEASE! Show use some pictures, please?

I realize that you may not want to post until you reach certain milestones but I find it hard to get a mental picture of what you are going to do without some photos.

 

[salty joe]

Wow, quite the project. I love it! Is there a way a high powered airlift would be useful somewhere? IIRC, a 140W air pump can lift about 1200 gph 3-4 feet. I agree, some pictures every step of the way would be interesting, useful, you name it-let's see some pics!

 

[dave willmore]

I think this is the part of the plan that will fall short. If I understand you right, this is how the cycle would work:
-fish poop feeds the adult brine shrimp
-from the energy gained in feeding on fish poop, the adult brine shrimp produce baby brine shrimp
-the baby brine shrimp serve as food for the fish/corals
-from feeding on the baby brine shrimp, the fish generate enough fish poop to keep the cycle self-sustaining.

There is no way that this cycle could be self-sustaining. In each step, a great deal of energy/nutrients is lost. You need to be adding into this system in some way, and not in a minor way at that. You could add to it by way of feeding the fish directly with other food or dosing phyto for the brine shrimp. IMO, it will probably take both methods to keep this system sustaining.

You're right that this cycle isn't self sustaining, but that is part of the point. As waste nutrients get converted into fish and coral biomass the water quality increases. As the corals eat plankton and grow in size they uptake nitrogen from the water so itmust be continually added to the system. But adding food is easy, converting detritus to live plankton is the goal, high water quality is the side benefit.

I disagree that energy/nutrients are lost in each step, it is continually converted between planktivore and detrivore. Yesterdays detritus becomes todays bacteria. detritus is nearly all eventually converted to bacteria which is converted to brine shrimp mass. Even if the food conversion efficiency is only 5 percent per day, the whole system approaches 100 percent efficiency as the brine shrimp waste from 2 or 20 days ago is converted into bacteria.

And i totally agree with you that phyto dosing is a good way to convert extra nitrates into shrimp food and needs to be part of this cycle, and that new energy must be added each day in the form of light.

 

[norskfisk]

Nutrients are not lost in every step, but energy is. Unless you add some energy "producing" step to the system the energy deficiency will cause it to fail in keeping disolved nutrient levels down. Animals can't get enough energy from their own feces having been made into biomass by detrivores. You need to feed the nutrients to algae that can turn them into biomass. The algae will turn all the nutrients into biomass where as the detrivores will only be able to use a tiny fraction because they lack energy.

 

[dave willmore]

Jon, you are quite right. When 1,000 calories of baby brine shrimp is eaten by corals and fish, perhaps 3% of that food is converted into weight gain and another (guessing at 10 to 30%) is energy expended by swimming and digesting, then their poop only has some 700 calories. So it takes bacteria biomass to build B vitamins and light energy for algae to build lipids and fats from the minerals and nitrates to feed the fish again.

Thanks for pointing this out. I assumed that a 3% food conversion efficiency would mean that the fish poop would have 97% of the calories of the original food, but you've helped me understand that the percentage will be far less. I thought that 100 pounds of detrivores would balance 100 pounds of fish and corals but you point out that I need the additional step of 100 pounds of algae and bacteria to be primary producers.

Do I have this right?

Although the algae refugium at 500 gallons seems large, in proportion to a 3,000 gallon display tank it may still not be large enough. Even though the greenhouse is in full sunlight I will cultivate additional phyto. I plan to use nighttime LED's over the algae refugium and the phyto to stabilize pH, but it could also serve to boost phyto production.

 

[norskfisk]

Yes, you've understood it now I think. I am not sure if your weight ratios are given to be exactly 1:1:1, but they need to balance each other, so the main point is right.

Actually the biggest energy loss doesn't come from the transition fish food -> Fish excrement. It is probably right to assume only 30% loss there (or less). It comes from the fish excrement -> BBS biomass. Here it is something like 97% loss. So you're probably left with 2% of the food energy when it comes back to the fish. That is where the primary producers come into the picture: Getting that energy quantity back, from light. (I guess the earth isn't a self contained ecosystem as it need energy from space all the time ;-)).

 

[dave willmore]

Jon, I don't understand why the conversion of detritus to BBS biomass would be so low. As a detrivore, artemia are famous for growing on low quality foods and after just a few days time their feces are converted back into bacteria to be consumed as food for the second time.

In theory if I fed a kilogram of detritus to the artemia each day, they would only convert 5% into shrimp biomass on day 1, but on day 2 in addition to a kilogram of new food there would also be 950 grams of feces from day 1, some of which is incorporated into the bodies of new bacteria. After a few days (or weeks) worth of conversion by bacteria, it seems to me that much of the shrimp excrement would be reprocessed into new bacterial biomass if it were dark, into algae biomass in sunlight (not factoring predation of the algae).

I understand if I am wrong, it won't be the first time today. But it seems that cumulative bacterial conversion of artemia excrement should be higher than 2%. I don't remember studying this in school biology so I am no expert. could it be 2% conversion on day 1, 3.95% on day 2, 5.9% on day 3, etc. because of the buildup of nutrient levels?

I will have a lot of sunlight and algae in the system, but I was hoping that processing fish detritus through the "shrimp filter" would reduce the waste by much more than 2%. How far off base is my assumption that bacteria reprocess waste into edible shrimp food?

 

[larrypoe]

wouldnt some of this energy lost (say from what the bbs/abs use for swimming, or any other gap in the a-to b-to c-) be recouperated from photosynthesis though the lights and natural sunlight(through windows in the sunroom).......the same way it is from the sun in the "outside" world?

while this project is FAR outside my little mind, it has me interested enough to keep track of its progress :dance:

 

[norskfisk]

When an animal's body takes up useful substances from the digestive system, or a bacteria takes them up from the surrounding environment a very large portion of them (90%+) are simply burned as a source of energy. The result is CO2, H2O, ammonium or other disolved non-energy containing substances. This is where you lose the energy. Feces feeding helps, but not really in a significant way. It may at best allow the animals to utilize the food twice as good as other animals (leakage and bacteria steal a lot), but 90%+ is still burned.

The only way to get the energy back is by photosynthesis.

You can have an aquarium system where you don't feed. I am experimenting with these things myself and I currently have a test system going that has been up for 9 months. Many animals have been growing fast all the time and I have not fed anything, I have only added algae fertilizer and light. But the algae are fundamental.

 

[dave willmore]

wouldnt some of this energy lost (say from what the bbs/abs use for swimming, or any other gap in the a-to b-to c-) be recouperated from photosynthesis though the lights and natural sunlight(through windows in the sunroom).......the same way it is from the sun in the "outside" world?

while this project is FAR outside my little mind, it has me interested enough to keep track of its progress :dance:

Larry, you are correct. Norskfisk first points out that caloric content of fecal pellets is so low that 1,000 grams of detritus may only translate into 20 grams of BBS loaded with fats. In concept, I know he's right.

My point is that when bacteria eat detritus they also assimilate nitrates and minerals into new bacterial biomass food. I find it hard to believe that one bacteria can multiply into a hundred thousand while only converting 2% of waste into bacteria biomass, so I think (hope?) his 2% figure is low. And many other types of zooplankton absorb nutrients directly from the water similar to bacterioplankton.

In the larger picture Norskfisk is right a second time. In the presence of light, algae absorb nutrients much faster than bacteria, so light recycles low calorie waste into high calorie food. Generally speaking plants are good at creating fats but poor at making B vitamins, while bacteria are good at creating B vitamins but poor in making fats.

Artificial light is expensive so my tank is in a greenhouse where large refugiums balance higher predators (fish and coral) with primary producers (phytoplankton and macro algae). Detrivores like brine shrimp and bacteria aren't primary producers per se but they are an important step in converting waste back to live BBS food.

My system and Norskfisk's are intended to let plankton survive their whole life until eaten. I replace high speed pumps and skimmers with slow propellers, filter feeders and lots of algae. I hope that clouds of plankton and full sunlight can push the envelope of what can be kept and bred.

But the key is balance. The brine shrimp sump is conical so feces drop to a point where a submersible pump sends them to phyto and macro algae refugiums, then on to the display tank. If Norskfisk's 2% figure is correct then most of the accumulated brine shrimp poop should go to the drain and most of my fish food should be frozen food cubes. If the 2% figure is low, much of the food will be recycled as live zooplankton or live algae.

Keep up your observations and keep pointing things out.

 

[dave willmore]

Norskfisk, if you are accurate that artemia will only convert 2% of the detritus to BBS, then I should radically change my artemia refugium. I don't mind cycling fecal pellets and nitrate water through phyto reactors but that brings up a more important question: why waste high quality phyto on artemia when it could feed calanoid copepods or directly to the display tank?

Because artemia are so hardy it would be easier to feed them flour and a selco substitute (fish oil/lecithin/vitamins) to satisfy their caloric needs and use the phyto for the calanoid copepods or to gut load rotifers and BBS.

If your 2% converstion rate is accurate then my water quality would be better if I just drain all the collected detritus from the bottom of the settlement chamber directly to the waste pipe. How accurate do you think this 2% figure is?

 

[dave willmore]

And if I'm not going to waste high quality live phyto on artemia, I should increase the size of the copepod tank to 1,000 gallons. They have much lower nauplii production than artemia and need much higher quality water and food.

In the same vein, I assume that adult artemia will predate amphipod nauplii, so a dedicated amphipod refugium with high nutrient water (and sodium light?)should grow the cyanobacterial mats that amphipods like so much. So perhaps some of the detritus from the settlement chamber can still be recycled through phyto reactors and amphipods.

But your point there may be the same, it may be easier to flush the detrital waste and give a high calorie food directly to the amphipods in addition to cyanobacteria. If there are no predators, amphipods should stay out in the open and feed all day.

What does everyone think?