3D Printed Spray Bar: DIY spray bar/manifold for jellyfish tanks

My apologies for the break in posts, hopefully this post will makeup for it! This is something cool I’ve been working on this summer… a 3D printed spray bar for pseudo-kreisels. As far I know this is the first of its kind…

3D Printed Jellyfish Tank

3D Printed Spray Bar in Sketchup 8

Using the free version of Sketchup 8 I built this model of an 8″ wide spray bar. As you can see there is a barbed fitting on one end to connect some 1/4″ tubing for the supply and 16 evenly spaced outflows to drive the current in the tank. The spray bar is angled to match the angle of the screen for a snug fit in the tank. There is also a flange on the far side of the model to help prevent it from being pulled off the tank. After printing 5 different versions of this model, I finally found one that worked. We used a MakerBot Replicator 2X to print the models.

3D Printed Spray Bar

3D Printed Spray Bar in the Maker Bot

This was the final print that made it all the way through, there were various printing errors: clogged print heads, ran out of material once, the print fell over, warped too much and the print would not stay on the table. Notice how in the final print above there is a tear-away support piece that I had to design in order to support the print. When you build an angled object you are going to need something to build on. I also ended up using double-sided masking tape to keep the print on the tray because sometimes the MakerBot would pull it off and start spewing plastic spaghetti strands all over.

3D Printed Spray Bar

Print Time

Each print took six hours! A good overnight print job. I could watch it for about 30 minutes before I had to leave.

3D Printed Spray Bar

Tear off supports

Here you can see me  bending off the support and raft (the raft is the flat piece on the bottom and acts as an additional build platform, which can help prevent warping). The raft is from the Skeinforge slicing engine (the software that tells your bot how to print your model), I ended up choosing the Skeinforge engine because it gave a much better quality print. Since then, MakerBot has made some significant improvements to their own default slicing engine, but I still don’t like the complexity of their raft. The Skeinforge engine uses a nice simple grid type raft.

3D Printed Spray Bar

3D Printed Spray Bar in use on a small pseudo-kreisel

Here it is in use, pushing some little Mitrocoma medusae around in a 1′ pseudo-kreisel or “PK” for short. This print did leak a little bit at high pressure, I later found that I needed to properly face all of my polygons in the model before printing. Sketchup uses polygonal drawings that need to be converted to STL models, or triangle based models. If you don’t face your polygons properly then the printer will not print some faces and produce errors or rough surfaces. For example you can see the rough end of this print closest to the camera… that face should have been white in Sketchup, or an outer face… not a blue face which would be an inside face. This print was also slightly warped, something that could be avoided next time by using PLA plastic, a biodegradable plastic that is more rigid. When designing your own spray bar remember that you need the end of the spray bar to be below the water level, measure carefully when drawing your model in Sketchup. I hope this spray bar can serve as inspiration for more 3D printed applications for jellyfish tanks. If you come up with your own print, please send me some photos and I will post them here.


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DIY Jellyfish Aquarium – The Ecopico by Ecoxotic

Your Summer Project: DIY Jellyfish Aquarium Using the Ecopico

I was lucky enough to receive an Ecopico from Ecoxotic recently to try and figure out a way to turn it into a jellyfish tank. I’m happy to report that I’ve had several moon jellyfish  living in the tank now for over a month with minimal care. Read on to see how to build your own jellyfish aquarium…

First, the obvious, you need to get an Ecopico. There isn’t much to setup, just clamp the light on to the back of the tank. Some plastic clips support the glass lid. You can check out the basics on setting the tank as a normal fish tank here.

DIY Jellyfish Aquarium

Ecopico DIY Jellyfish Aquarium

In addition to the tank, you will need a few supplies; an under gravel filter plate with air tube, a small air pump, a valve for airlines, some airline tubing and rigid airline tubing. All of these can be found at your local pet store.


You will want an under gravel filter that has a modular air tube so you can place it wherever you want. Some of them are fixed in place, you don’t want those. This one at PetSmart is what I used. Connect all the filter plates together and place the air tube in the middle as shown below. You may need to cut a side off one of the plates to make it fit in with the rest.

DIY Jellyfish Aquarium

Under gravel filter plate with centered updraft tube

Center your gravel plate in the EcoPico, you will want the substrate to hide the plates around the edge of the tank…

DIY Jellyfish Aquarium

Center the under gravel plate in the EcoPico tank

Next you need to choose a substrate. I prefer these small, jellybean #1 size, glass beads from American Specialty Glass. You’ll need at least 2″ of these beads, which works out to about 7 pounds worth of glass, I ordered a 10# bag so there would be plenty just in case I needed to add more. You can of course use any other glass bead you can find, sometimes dollar stores carry these beads. You just need to use the right size bead, read here to find out why! You don’t want your jellies getting sucked down into the substrate. Go ahead and add your beads by hand, don’t just dump them in carelessly.

Now connect the rigid airline tubing to the airline and pump. Feed the line through the Ecopico LED bracket, it helps to hold it in place. I used some nice black silicone airline, as it blends in well with the LED bracket.

DIY Jellyfish Aquarium

Place the airline tubing in the updraft tube

You should be ready to add water! For salt mixes, I use E.S.V. B-Ionic. This salt comes in  3 parts, the sodium chloride crystals, magnesium crystals and liquid trace elements. Because it comes in 3 parts like this it mixes much faster and clearer than other salt brands. Having large undissolved salt crystals in your water is not optimal for your jellyfish aquarium! You will want to mix your salt in RO/DI filtered water or distilled water, do not use tap water.

DIY Jellyfish Aquarium

Ecopico Jellyfish Aquarium

After you fill the tank be sure to smooth out the beads. You will want to allow some time to seed your tank with bacteria to drive your nitrogen cycle but it is possible to add jellyfish immediately. I added 3 small and 1 medium moon jellyfish immediately and performed water changes everyday for a week to keep ammonia levels down. Keep this in mind when setting up a small tank like this, ammonia will build up quickly and it is best to stay ahead of the game before it can become a problem for your jellyfish. A typical sign of ammonia being too high is that the oral arms will look ‘burned’ off or severely shortened, the tentacles may also be shortened or not extending. If you see this you need to start changing water. An easy way to manage your water changes is to buy a sturdy Brute trashcan and mix your salt all at once, effectively creating a saltwater reservoir, this way you aren’t mixing salt every time you want to do a water change. You can easily cup out water and then go get clean water all ready to go. If you do keep a reservoir you will need to stir it because it is possible for the water to stratify with different layers of salinity over time, if you’re using the reservoir regularly though this usually isn’t an issue.

Once the jellyfish are in the tank you are probably wondering; how much air should I bubble? It is difficult to count bubbles when they’re moving so fast, so here is a video of what your bubble rate should look like…

We are going to follow the same “rule of flow” for jellyfish with this tank as with any other; we want just enough flow to keep the jellies off the bottom and suspended, no more than that.

As for feeding, I feed live brine shrimp several times per week for this setup. I like to alternate feedings with water changes, so for example… on Monday I’ll feed some brine shrimp, Tuesday I’ll do a water change, feed again on Wednesday, Friday and Sunday with a total of 3 water changes on Tuesday, Thursday and Saturday. You can feed other products such as R.O.E. or Rotifeast by Reed Mariculture but live brine shrimp, or even live copepods are now available from AlgaGen, are the preferred foods for moon jellyfish.

The jellies have been flowin’ and growin’ in this Ecopico for over a month now, I am confident that you can emulate this success. I tried to leave the tank alone as much as possible, even missed a few feedings and water changes to really ‘stress test’ this DIY jellyfish aquarium. It works great! That being said, let’s talk about expectations for this setup… if you are looking to keep jellies for say around 6 months then this is a great tank for that, but if you want to attempt to keep jellyfish for over a year then you will need a more robust setup, such as the Cubic jellyfish aquarium. Keep in mind that moon jellyfish are seasonal animals with what is most likely a natural life span of about 6-12 months. Now that I’ve set this expectation, if you can get your moon jellyfish to live longer than 6 months in the Ecopico, then I want to hear from you! I’ll gladly post your tank photos here on jellyfishaquarist.com.





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My jellyfish is stuck!

Uh oh, is your jellyfish stuck? Is your jellyfish getting sucked into the gravel? If you are using an air-lift driven jellyfish tank there may be a very simple solution. First let’s look at how your air-lift works so that you understand why your jellyfish is getting stuck…

Jellyfish Tank Air Lift

How a jellyfish tank air lift works.

In the simple diagram above, the air is moving up the lift tube in the middle. As the bubbles rise you are displacing water in an upward motion, this sucks the water down through the gravel everywhere outside of the tube. When you have the air turned up high enough you can have too much suction through the gravel or substrate…. then your jellyfish gets stuck. If your jellyfish is actually getting sucked down into the gravel then that substrate is too big for your jellies! Now look at the differences between the two diagrams; the drawing on the left shows larger substrate with big arrows representing the  strong water flow while the drawing on the right shows a much finer, smaller, substrate with more, small, arrows showing a diffuse water flow. Because the larger substrate allows more water through, the suction tends to be very strong closest to the lift tube. The smaller substrate does not allow this, instead it breaks up the flow because the substrate is denser. So by using a smaller, denser, substrate you can help prevent your jellyfish from getting stuck!

Jellyfish Glass Substrate

Jellyfish Glass Substrate

Above you can see some common glass beads found at your local dollar store vs. some nice “jellybean” sized glass pebbles that work a lot better at helping to keep your jellyfish where they should be! Where do you find such beads? Here! Check out American Specialty Glass, they have a great aquarium section and you can order online. You will want to stick to the jelly bean size 1 beads or smaller.

If your jellyfish is stuck after changing out your substrate another trick is to diffuse the suction coming from the airlift itself by using silicone to seal up the under gravel plate near the base of the air lift tube. You can also buy a simple valve for airline tubing to fine tune and/or reduce the air flow which will reduce suction.


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New Jellyfish Exhibit Opens at Vancouver Aquarium

Jelly Invasion has just opened at the Vancouver Aquarium in British Columbia. Denizens of the Pacific Northwest should definitely check out this jellyfish exhibit as it features a tank you won’t find anywhere else… a giant tank full of spotted jellies! There are over 1,000 spotted jellies on display, a sight you won’t find at any other public aquarium. Check out the spotted jelly webcam! Spotted jellies aside, there are 16 other jellyfish displays to check out. Jelly Invasion is accompanied by a show, Jelly Delia chance to actually eat some jellyfish! You might also get to see the “edible jellyfish”, Rhopilema esculenta, on display…

Edible Jellyfish

Edible Jellyfish at Vancouver Aquarium

Go see Jelly Invasion!


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