FtBCon news »« God must not have liked his game

You asked, I deliver the fish porn

Since everyone insisted, here’s a photo of our incipient zebrafish system, built by my student Josh.

tankphoto

What it is is a set of ordinary plastic shelving with some custom built plastic trays to catch water overflow, and then an array of simple 2-3 liter tanks (the smallest size Kritter Keepers, if you must know — you can get them for about $2 each). There is a 110 liter reservoir tank down below, with an immersible pump that can generate a flow of about 1900 gallons/hour, currently greatly throttled down since we only have a few tanks in place. Water is pumped out of the reservoir to two places: 1) towards the ceiling, where the PVC plumbing splits — with valves, we can select to have the water pumped right out to the sink nearby, or to a bypass line that just has the water going up and back down, or in normal operation, to a line that has a big hunk of 3″ PVC pipe packed with bioballs and charcoal for filtering, and 2) to a big bucket of sand for additional filtration. Water is just flowing all over the place here.

Most importantly, the main outflow line is tapped in 3 spots to some irrigation hose leading to six of these nifty little widgets that provide a trickle of water out nine smaller drip lines, which lead to the fish tanks. It’s amazing what you can find in hydroponics gear. If ever Minnesota legalizes marijuana, I could also cycle fish water (mmm, rich & tasty fish poop) into racks of plants and pay for all this stuff.

Here’s a quick and dirty diagram if that explanation doesn’t help. Not that the cartoon will necessarily help, either. Blue circles are valves. Arrows indicate the direction of water flow.

tanksystem

It’s been running for a couple of weeks solid with no problems (I wish I could say the same for the backup system we set up yesterday, which blew gaskets all over the place and made a mess overnight), so we’ve actually put a few fish in there. With any luck, we’ll have embryos this week!

Comments

  1. yazikus says

    That is truly awesome. I wish I were handier with the tank making, I’ve been wanting to do a little 20 gallon riffle tank for indigenous minnows. I’m a bit intimidated by all of the tinkering it takes though.

  2. moarscienceplz says

    Yeah, I noticed the bulging side too, but it also looks as if a couple of the shelf support legs are going through the bottom of the reservoir. Is it just an optical illusion? It can’t really be designed that way, right?

  3. gillt says

    I’ve built and maintained lots of zebrafish systems big and small and know it’s a lot of work!

    Depending on stocking density, you could always just fill the reservoir with those blue plastic bio-balls–they float and shouldn’t clog the pump intake. And I would recommend an inline UV sterilizer, but those can be expensive. A cheaper alternative is a submersible UV filter commonly sold in online pet stores or ebay for about $40.00, which will fit in that sump. To maintain alkalinity, which stabilizes pH, a mesh bag of aragonite (crushed coral) in the sump wouldn’t hurt. I imagine evaporation is an issue. Are you drawing water from the lab faucet to make up for evaporation or do you have an R/O system? Electricity and water: GFIs or grounding probe? Where’s the brine shrimp hatchery?

  4. says

    There’s a container of bioballs floating in the reservoir. I’ve got a UV sterilizer…we haven’t put it in place because I haven’t seen the point. We like our bacteria. We’ve got an RO line right next to the tank, easy to fill the system. The brine shrimp hatchery is a couple of flasks in an incubator on the other side of the lab.

    The sterilite container is bulging inappropriately. We don’t like it. I’m going to replace it sometime soon with something sturdier.

    The shelf support legs were cut to rest on the bottom of the tank.

  5. Tethys says

    The sterilite container is bulging inappropriately. We don’t like it. I’m going to replace it sometime soon with something sturdier.

    I have a 50 gallon/189.271 liter aquarium with metal stand taking up room in my garage that I would happily donate to the fish lab if you want to fetch it next time you’re in the cities.

  6. gillt says

    Ha, you like bacteria on the bioballs not pathogens in circulation. With good quarantining UV is less of a necessity and just a piece of mind. Instead of plastic storage bins, used aquariums on craigslist typically sell for $1 per gallon. A 55 gallong should do the trick.

  7. Nerd of Redhead, Dances OM Trolls says

    My improvise sense is saying a short dowel under the lip on the Stearlite tank to straighten the bulge slightly, with a short bungy cord holding the dowel to legs, and assisting to reduce the bulge, might be a temporary fix to prevent the bookstore from getting wet.

  8. moarscienceplz says

    The sterilite container is bulging inappropriately. We don’t like it. I’m going to replace it sometime soon with something sturdier.

    The shelf support legs were cut to rest on the bottom of the tank.

    You could make a girdle to hold the tank’s shape. A sort of picture frame made of 1x2s, some water resistant glue and a few brads could be held in place with some wires going through small holes in the tank rim.

    Once you have all your Kritter Keepers filled with water on the shelves, that’s a lot of weight pressing on that thin plastic tank bottom from the ends of those hollow legs. I’d be worried they could punch right through. If you have to have that arrangement, you might try getting one of those stiff sheets of plastic that are used in 3-ring binders to keep the papers from pinching. Place that between the legs and the tank bottom to spread the force.

  9. Ichthyic says

    Instead of plastic storage bins, used aquariums on craigslist typically sell for $1 per gallon. A 55 gallong should do the trick.

    yeah, I’ve always found, whether doing research or just for home stuff, that buying aquariums on trademe, or ebay or whatever was always more economical, and faster, than building them myself.

    it’s one of those areas that has a quite large amount of trade in it, and aquariums have tremendously poor resale value, making it a total buyers market.

    I often get good quality items at less than 10% of the original retail value. My grant dollars went way further.

    true, the mishmash of slightly different sized items often did not look pretty, but I always have had more pragmatism than style.

    this said, not for the benefit of PZ, who has already finished his basic design, but for any students who might also be thinking of doing experiments with fish, or even those thinking of taking up fishkeeping as a hobby.

    don’t buy new stuff, seriously.

  10. Ichthyic says

    The sterilite container is bulging inappropriately. We don’t like it.

    good, because it will definitely fail within a month.

    that kind of plastic deforms under stress.

  11. Ichthyic says

    … why not use a steel tank for that part? doesn’t have to be see -through, right?

  12. FossilFishy(Anti-Vulcanist) says

    Heee, I love this. Especially the part where I clearly know nothing about fish tanks and water circulation. It all seems to make sense to my ignorant eyes except where the filter is. I wonder why it’s after the tank feeds rather than on a separate like like the sand filter. The only think I can think of is so that the system continues to flow at the same rates when the filter is bypassed, maybe?

  13. rodw says

    How do you get the solids out of the bottom of the fish tanks? It looks like water is overflowing out of the tops of the tanks. I WANT one!

  14. says

    Bioballs provide surface area for microbes that you want so they can maintain a larger population and do more of the chemistry that you want them to do. I don’t know what the barley is supposed to do. Maybe it’s cheaper or higher surface area than the plastic ones?

  15. says

    The reservoir tank is a disaster waiting to happen. Replace it ASAP. In addition, you do not want plasticizers leaching into the water where your danios live. I’m a chemist; I’ve kept and raised fish; and I know what’s in plastic. Glass only, if you want to trust your results.

  16. Alan Hutchinson says

    We use a similar steralite container for my daughters pet turtle. I took a spare piece of 2×4 cut notches in the middle and tied it to the container to prevent it from bulging. I’m not sure how to share a picture on here, but I shared it on G+.

  17. lochaber says

    I haven’t personally checked, but I’ve heard PetSmart has their $1/gallon sale going on about now, if there is one near you – I got a 40B (36″long, 18″wide, ~16″high) for ~60 (tax on full price). I don’t know if they always have 40B (I didn’t see any in a nearby store at the last $1/gallon sale), but they usually have 20H, 29, and 55.

    If you can’t find anything suitable, might be able to make a simple plywood box to support/brace that resevoir, or use a big trashcan or something.

  18. F [is for fluvial] says

    Sterilite cracks like… things that crack easily and often. I’m with the “replace it ASAP” crowd. Food-rated Rubbermaid if you want to go the plastic route.

  19. Rumtopf says

    Yay aquariums!
    I only have smaller tanks, but when I get my dream big tank I’ll be turning one of my current tanks into a wet/dry sump. For now I have a waterfall style filter for one and an external filled with ceramic rings/sponge/floss for the other, larger one(and extra sponges on both intakes, great bacteria farms and the shrimp love to graze on the biofilm they grow).

    Hope it all goes well with the new fishy additions. :D

  20. Goodbye Enemy Janine says

    Fish porn
    Fish porn
    Roly poly fish porn

    Fish porn
    Fish porn
    Eat them up
    Yum!

  21. says

    I wouldn’t be able to sleep worrying about that plastic tank. It’s going to go, sooner or later, probably sooner. And when they do go, they break apart all at once; no little cracks, no warning.

    (Learned the hard way.)

  22. Menyambal --- Ooo, look! A garage sale ... says

    I agree, Sterilite is not good. It does crack.

  23. Ichthyic says

    might be able to make a simple plywood box

    actually, the tank itself can be a simple plywood box, seamed and bolted, maybe with a cross-brace or two, and sealed with epoxy or fiberglass on the inside.

    done that before too.

    takes time to cure though.

    still say a steel box would work, and the uni probably has one in it’s junk pile somewhere.

  24. Thumper; Atheist mate says

    Um… the big resevoir tank looks a lot as if it would fit neatly underneath the shelving if you just moved it half a foot or so to the right. You’d have to extend some piping and shorten others, but surely that’s better than risking a shelving leg going through the bottom of the resevoir?

    That said, I assume you would have thought of something like that, so it may be merely the perspective of the photo which makes it look like it would fit…

  25. george gonzalez says

    Those HDPE containers seem to have a frightening tendency to crack or shatter for no discernible reason.

    Also the chance of one of N hoses, where N > 10, popping off their connection point, over a year, is a bit on the uncomfortable side.

    A Radio-Shack basement water alarm *might* be a good idea.

    Also don’tcha have to worry about those pseudo-steroid plasticizers leaching into the water? Or do you want or can tolerate slightly less than manly-men fish?

  26. tmscott says

    Hey PZ,

    Well, you have a start.

    Ditto the comments re: the sump, you will soon have problems with that. Since you really only need the sump as a surge volume, why not employ a couple of smaller containers that would have more surface to volume and thus more wall strength. I think that you will also come to regret cutting the shelf support leg and putting it in the sump, for a number of reasons structural, biological and logistical.

    I also see a potential problem with your sand filter. You are only using a very small volume of the sand you have, that which you can fluidize, the rest is wasted volume. The real problem will occur when the bacterial biofilm coats the individual grains of sand and changes their particle density to the point where they float out of the bucket. Be sure that your pump’s intake filter is sufficient. It would be prudent to use the popular “U” tube design for your fluidized bed biofilter, it makes better use of the media, and contains it better as well.

    I would also suggest that instead of putting your components on one pump, that you use two, one for tank flow and one for filtering and processing. The flow, and more importantly pressure, requirements of the two are considerably different, and you will get better efficiency, easier adjustment, and more life out of your pump motors if you divide the job.

    It’s also been my experience that hose barb fittings and vinyl tubing under pressure eventually lead to grief. Maybe not soon, but eventually, and perhaps during and experiment. Pipe unions are your friends.

    Pump pressured delivery lines also lead to inconsistent flows. Don’t forget that gravity is amazingly consistent. Pumping to a head pipe (with overflow) and using gravity head pressure ensures a more consistent delivery flow.

    On last suggestion, be sure to season the system well before you purchase your fish. Allow the system to run without fish for a few days, then exchange the water and repeat. On your last exchange, add a biofilter inoculum, either from an aquarium, an other system or commercial product, and some soluble nitrogen. Ammonium acetate works well, but so does Miracle Grow™. If you start with 5ppm total ammonia nitrogen (TAN), you with have a good start on both nitrosomas and nitrobacter populations by the time you get back to under 1ppm TAN. Expect both TAN and Nitrate levels to seesaw up and down a couple of times before they stabilize. Resist the temptation to exchange water, you need the differential to drive the equilibrium forward.

    Lastly please pardon my criticism, it comes too easily after 20 years of designing and building aquaculture systems.

    Tom

  27. zoniedude says

    Not really my area of expertise, but have you considered putting a T-junction inline with an upward pipe of a few inches that is capped? When the water flows it will trap air in the upward pipe that will work like a shock absorber when valves are turned on and off. Thus saving stress on your other joints and connectors.

  28. Lonely Panda, e.s.l. says

    Definitely replace the Sterilite bin, especially if you might throw UV into the mix. I tried to use one to store birdseed on our porch and the most exposed side of the bin turned brittle and started to crumbled in only a few months. It wasn’t even in direct sun.

  29. madtom1999 says

    I saw stuff like that 40 odd years ago in Coos Bay – but without the hideous prophylactic plastic stuff. Far too kinky for me!

  30. says

    So the action items are these: replace plastic with glass; get a stronger, glass sump; install the UV sterilizer so you don’t spread one case of ich to the whole setup; make sure hoses are secure and not shedding organics into the water; and consider getting two pumps, for filtering and water flow.

    Any breeding cages to sequester gravid female fish or seaweed for hatchlings to hide in?

  31. says

    So you’re studying the development of fish eggs in tanks where volatile organic compounds are leaching into the water? Mightn’t that affect your results? And what is the result of leaving out all the lovely muck that they normally breed over?