The History of Pico Reef Biology

Pico Reefs | 25th February 2010 | Article by Brandon Mason | View comments (136)

The ‘tank’ as of 24th February 2010

The idea for a truly long term micro/pico reef (for this article, one gallon or less) came to me as I was graduating college and searching the early internet forums for ideas on small reef aquaria in 2000-2001 to see what was possible and establish the current limitations of small marine aquaria. The smallest I could find, in the history of reef aquarium work altogether and in a lot of searching online, were 2.5 gallon tanks- some ranging back into the 1970’s (Thaler Puddle, Dr. Ellen Thaler for example) and an article on interviewing DC Potts about his successful pico tank from the late 90’s.

Feb 20th 2013:

In 2001, even pictures of quickly-assembled gallon and half-gallon experimental aquariums (now common) were not available across the web, especially those using synthetic saltwater, so it was truly untested waters to work with half gallon aquaria that had to meet strict criteria to be valid in my opinion: they had to develop and sustain a diverse population of stony corals, benthic organisms and coralline algae, meet all water support needs with reasonable care (for example, no daily water changes) and they had to last-as long or longer than large aquaria without going eutrophic (high nutrient/algae dominated) relying on biology, not mechanical devices, to run the micro ecosystem. In hindsight they would break every rule the current establishment held against ultra micro aquaria, using simple science anyone could replicate, and the vast resources of the web had the friends I’d need to do it.

Lastly, they had to stand the test of master aquarists across the internet when reviewed-the technophiles like the guy at the rock concert who can tell when the guitarist messes up a single note. Emerging from all that scrutiny and time in preparation should be a new way keeping corals in the home…it’s still evolving as we all exchange ideas and new designs on blogs like this one.

The Reefbowl

One day when walking through Wal-Mart and thinking about design options, I noticed the curved 1.5 gallon vases for a few dollars and thought that would be a neat trial run, a seven dollar reef aquarium. When looking at the vase and thinking about substrates, pumps, etc it dawned on me the little plastic dishes I was using in the lab to keep pothos vines watered seemed the exact diameter of these large vases, maybe it would function like a lid if inverted? So I took the vase home, filled 1/3rd of it with oolitic substrate and saltwater and decided to bubble it instead of a pump, primarily I wanted to use gear I already had and the old aquarium pump happened to be there.

I knew not to add animals; this was just to test heating and salinity control. Well in four days the salinity had only increased from 1.023 to 1.024, the water line dropped only a quarter inch, and that was it-the design was lucky and worked perfectly with no further modifications. For the first time, a gallon reef aquarium had surpassed the top off requirements of a 100-gallon aquarium without complex equipment, and it was easily repeatable to anyone who wanted to try with common Wal-Mart supplies. The air stone met all the circulation requirements of the tank, it kept CO2 from accumulating so it lent strong pH support, it is the absolute ideal way to run a vase reef for these reasons, above any water pump. No animals in situ mind the air bubbles whatsoever… Normally, this combination of gear would be frowned upon in the established reef circles, so this presents another way to bend the rules unique to pico reefs.

The vase continued to evolve and it can be found by searching for anything with vase reef or reefbowl (non spaced) in the wording, there are thousands of threads about it all over the web because I spend a lot of time promoting, discussing and helping others replicate the art. My current vase reef is 4 years old and I expect it to run much longer barring hardware failures (knock on wood). Recently my friend Mark K. (Warlion) developed the vase even further by drilling the line access into the vase, rather than over the lip. This has added two more days between top offs, an unheard of maintenance schedule for any reef aquarium.

Additional pico reef photos can be found here.

The 1/2-gallon PalmTop Reef-No Evaporation

As the reefbowl sat and inspired me further, collecting simple corals that got along well, other ideas such as complete sealing came into mind and one day it snapped in my head to simply include a refugium as a rear subdivision in a tank, obscured by a false reef wall, to use photosynthesis to pump out oxygen under a sealed lid. This would bind respiratory waste CO2, stop evaporation altogether, it would bind up nitrogen and phosphates in the macro algae to some degree, and combined with weekly water changes (something not procrastinated if only one gallon and three minutes) the Palmtop Reef was assembled out of a special beta tank available at the time.

The first long term half gallon reef aquarium documented on the internet, and still the only fully documented sealed reef aquarium (non evaporating) of any size, this helped pico reef keepers find a unique niche among large-tank husbands who were once sure such a thing was impossible I could see in the web forums. Together online we worked out a carbonate dosing system for the micro tank which produced miniature acropora tabular growth and copious coralline algae, this indicated the ion support was spot-on even with no testing of any water parameters outside of salinity! My simplicity requirements had been met–no exceeded.

There was so much helpful input from other posters along the way to help me further my cause, Lunchbucket (Eric Peterson) is a fine example, he and I go way back in the reef forums (before 2003) and his tanks were a source of wonder for me as well along with many other board regulars who chimed in with support and help as needed …all the help needed was on the internet and for that I am so grateful.

Chemical/Physical Changes

Over the years in discussing forum threads about keeping marine aquaria in odd shaped containers, we are starting to see how shapes beyond the standard open square aquarium greatly change, and assist, the keeper if they are willing to make tradeoffs. The first tradeoff is fish, don’t use them in any pico reef is my best advice. I have experimented with fish like gobies before, and don’t agree they should be kept in ultra small aquariums. By excluding fish in the design, there are no size restrictions for aquaria that can grow scleractinian corals.

For example, the fluted vase reef design is an absolutely critical shape for many reasons. The slant of the neck above the water line and under the lid forms a catch surface where the popping bubbles eject various fragments and wastes from the water column; this can be wiped periodically and is essentially a functioning skimmer. The lid rests on the inner diameter of the vase neck, something not possible in square tanks, and this directs the splatter back down into the bowl and away from the edges where salt creep would form in the usual situation around a lid, and it also seals the tank, taking it from a 2x daily top off opened to a twice weekly top off with a lid!

Continuing the ways container shapes change the physicality of a reef aquarium, Orb-type nano reef aquaria reveal an ever-increasing surface area for evaporation to occur as the water level drops (small surface area when full, large surface area approaching the equator of the orb or bowl) so the salinity increase is on an apparent log-scale just like pH, it’s not a consistent evaporation rate when compared to a square tank. Evaporation rates between days 3-4 are markedly faster than on days 1-2 on a globe/orb saltwater aquarium after a top off because as the water level drops more surface area is exposed to amplify water loss.

For total salinity control, small containers that can be sealed, and subdivided for plant growth, are the right size to use small lights and pumps that would otherwise overheat a larger sealed reef attempt and these small containers are also dwarfed by a basic desk fan when cooling needs arise during summer months. Knowing these variables ahead of time greatly hastens reef work in odd or small containers; this is helpful to keep in mind.

Just to mention a few final observations, which are better left as subject material for expert marine biologists, pico reefs are also changing what we observe as allelopathy or “war mechanisms” in scleractinian or “stony” corals because of the concentration ratios seen in these tiny tanks. How is it possible for 15 genera of coral, plus assorted invertebrates and mollusks, to share a gallon of water day after day in between servicing for years and not nettle the water into a mucus-laden soup?

These answers can be found in the further study of pico reef biology, there should be lots more to come over the new year as others make their observations known and we all continue to create a collective knowledge pool for the matter.

In closing, some people feel the micro reef designation will soon become the most popular in the hobby for a number of reasons listed in common nano reef articles (cost/footprint etc). A keeper or a future keeper of pico reef aquaria will have done much online research to get where they want to be since that is the only material available on the matter, so this networking combined with the use of maricultured corals and tempered experimentation should continue to bring our hobby into new homes at an astounding, and ethically sustainable rate.

If you have any questions or would like to discuss pico reef biology even further, be sure to leave a comment below.

About the author:

a unique passion for the smallest reefs since 2001... Discovering new techniques to forward coral husbandry and aquarium science is not size restricted, it's creativity restricted.

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136 Responses on The History of Pico Reef Biology

  1. Dan says:

    ah ok cool. im using led's at the moment, actinic blue from above and an rgb lamp shinning in from the side which is set on white most of the time but its nice to be able to flick it to all blue in the evening which makes a couple of bits of coraline that came on the live rock really shine.

    Whilst at my lfs today i noticed a few frags, which aparantly had fallen off other rocks, which were a few quid. So i picked up a couple of mushrooms and a tiny frag of gsp for £5. Theyve been in a few hours and the shrooms seem ok but the gsp has not opened up at all. Hopefully it will be ok by morning. It is close to the flow of bubbles, maybe that is annoying it a bit?

  2. Brandon Mason says:

    Both zoanthids and green star polyps (briareum) are very finicky about polyp expansion. In aged tanks you will almost never see odd behavior in them, but in newer tanks they are subject to stay closed for alarming periods sometimes…

    I have personally had green star polyps growing among airstone output so it is possible for them to 'ignore' it, but in a new tank with the usual instabilities relative to size and water care its really hard to say why some stay closed and some do not.

  3. Dan says:

    cool, cheers man. The mat/base of the gsp is still bright purple so im sure its still ok!

    I've had a move around in the tank, i wasnt very happy with the larger bits of liverock so i broke them up a bit, and i've move the gsp and air stone so the flow is a bit better! Once its settled down a bit i'll get some photo's up somewhere.

    Thanks again for lots of great advise, its much appreciated.


  4. Dan says:

    just a bit of an update, i ditched the gsp as it was starting to turn brown and i didn't want it breaking up and dieing in the vase. However whilst at my lfs today i picked up a few bits from there random frag tank. got another green shroom, a bright green hairy mushroom and a tiny branch/offcut from what i guess is a finger coral. i also picked up a hermit crab. all of which are doing great. and all for less than 5 bucks :-) ….. pics to come soon. what would you say is the best/most informative site or forum for pico reefs?


  5. Brandon Mason says:

    Ive always made the rounds between nanos forum, and

    I met Cerven from this blog on nano-reef, thats been a great community for networking with other hobbyists.

    there is much difference however in the required techniques for supporting gallon reefs vs nano tanks of any other size. Even the practices for a 3 gallon tank will not work long term in a gallon vase, they are a unique beast…I have searched the web for ten years to find all the information possible on gallon reefs, what I found is a lot of people not keeping gallon reefs like to give guesses on how to make them run (or they discourage the practice altogether)

  6. Dan says:

    yeah i've looked up so much info on vase reefs over the last month, and many a time i've seen someone saying that its impossible followed up by your post to this blog and a full explanation as to how they work. there is nothing like re writing the rule book!!! so far ive enjoyed this vase way more than my old ten gallon, i already have coraline growing on the rocks and i can change nearly all my water in about five minute… i'll get a blog going on one of the forums soon mainly to challenge the sceptics, and hopefully i'll get this vase to go for mutiple years like yours.


  7. DC Potts says:

    .Beautiful work.
    I hope someday you'll unlock the closed system pico.

  8. brandon mason says:

    can you post a link to a video or pictures of your setup

  9. giga84 says:

    Hi your setup is great. I am from south india and pico reef keeping is at its infancy here . I have setup my reef tank just like micamind – a cookie jar setup. I can't get coralife bulbs here for lighting. I guess i have to either order them online but the price is much high. I only have a live rock with lavender color coraline algae on it (almost 50% of the rock).I am currently using a phillips cfl (cool daylight) 11w 6500k 570 lm. We do get GROWLEDS ( will they be enough for my tank . my tanks dimensions are depth – 10 inches ;width – 7 inches ;length – 7 inches
    water height — 8 inches. Also can you feed corals with finely ground prawns. Because we don't get cyclopeeze here. I can't get frozen mysis is that enough.Sorry if i have asked so many questions its just i don't get much here.

  10. giga84 says:

    sorry i can get frozen mysis

  11. Dan says:


    Sorry for the late reply, here is links to a couple of shots of the vase.

    All was going well untill i had a problem getting some ro water and had to use deionized bottled water for a few weeks. This resulted in an insane algea bloom. This pics above are taken after i removed all rocks and scrubed them with a toothbrush and cleaned the glass.

    Im back using ro again now so i hope all will remain clean with my 100% water changes each week!


  12. giga84 says:


    Could you please help me out with my problem?

  13. Brandon Mason says:

    Giga sorry for the delay Ive been knee deep in several peroxide threads treating all kinds of aquarium pests, Im glad you got corals to start this relatively new science from your neck of the woods!

    Your feeding request is rather experimental, we don't know about the grinded up shrimp but its worth a try. At least you are making the particles very small for them to try to uptake, we will know if the coral polyp stays full/prominent over the corallite (retains its mass) in a few months.

    Keep me updated I'll try to respond faster next time!

    Dan the vase is sick its a neat shape Ive never seen in them! I noticed your lid fits on the inner diameter, so you should be seeing some of the benefits of partial sealing on your topoff requirements now. The coloration of the vase/light/corals looks great.

    My friend DC Im working on a flickr set of my build pics for the sealed reef. Sorry we lost touch in email but im glad to see you on here nano reef obi wan kenobee



  14. Dan says:


    Thanks for the complements.

    Yeah I have the lid on the inner seal and thanks to that I top off maybe twice between water changes. to be honest it would probably only drop 1/4 of an inch in the week anyway with the lid.

    Just a quick question, I`ve seen pics of your vase at the start of its life with just the live rock and you manage to get the rock aquascaped all the way to the top of the vase. Did you glue all the bits of live rock together? I ask because every time I put a new frag in, or change water……. or breathe anywhere near the vase I cause a rock slide and then spend ages sorting it out again which probably isn`t doing it any good lol!

    Going to start a thread on nano reefs pico forum at some point when I get a few more pics, see what the people on there think!


  15. brandon mason says:

    Yes! I must have ten full tubes of super glue gel used when the tank was new to hold all the frags

    But in time the corals plate over the glue points and are perma locked its just adelicate balance…

    I'll see your thread when you post it and the pics/shape is gonna go over well

  16. giga84 says:

    thx for reply what about the light doubt?

  17. brandon mason says:


    That light does not appear to be a reef spectrum light, no blue

    It might still grow coral and it might cause some algae growth. Feel free to experiment with any non standard approach and let us know how the experiment works

  18. Dan says:

    hey man.

    Sooooo my vase has taken a bit of a set back after my heater decided to stop working over the weekend, and of course it happened while i was away from the house for 2 days. Corals were looking all closed when i got back so i took out live rock did a 100% water change put corals back in with an old heater and then the next day bought new live rock and a new heater.

    At the moment corals aren't melting away but non have opened really, luckily its only a few mushrooms, rics and gsp but its still annoying after everything ways really starting to come together.

    I'll get some new pics of the new set up soon and hopefully that is all the hardware failure out the way for me early on.

    Oh one other thing, have you any experience/advise on favia?



  19. Seanathin says:

    It's cool that you've had this tank for so long, but it's ugly as crap.

  20. brandon mason says:

    Opinions vary, I recommend you set one up and post maturation pics that are better.

    Dan's is looking great I've been watching his nr thread, we need more than two on the planet so post up a third

  21. […] pico reef is generally considered to be a reef tank smaller than 5 gallons. People have successfully grown […]

  22. Carlos Padilla says:

    Im in the process of setting one up myself, i love vase reef picos.

  23. brandon mason says:

    Hi Carlos I'm glad you like them. People truly miss out on the stability of these compared to even larger tanks, getting up to 4 days and beyond on topoff requirements, without using an auto topoff system, changes the game of nano reef work considerably and is not something 100 gallon tanks can do

    Going on seven years now, so many larger and more complex nano reefs we see on board threads have come and gone, yet the vase persists indefinitely due to some key design and maintenance elements.

    I have designed it to have an indefinite biological lifespan, the external hardware is the lifespan controller. The tricks to feeding, water changing and sandbed maintenance prevent nutrient sinking and account for coral export.

    The location of the vase needs a consistent temperature below 78-79 degrees, so most homes and offices qualify, and they need consistent electricity feeds as the gallon reef won't tolerate a big power outage. But you provide those two conditions, and your vase if maintained correctly can last longer on the original setup than many large tanks we call inherently stable.

    Post us a link here to thread or pics of your vase if you'd like!

  24. brandon mason says:…

    I hope to make this the largest peroxide thread on the web in a few more months. Using applications I learned from, and perfected on the reefbowl in this article, we have a huge database of pictures and testimony on tanks up to 300 gallons.

    Pico reef biology is impacting aquarium science as a whole.

    one of the sps tanks in the thread is worth several thousand dollars, the method is reliable despite negative assumptions about using peroxide in a reef tank, maybe when the thread garners thousands of examples it will become more believable.

    Don't forget in 2001 nearly all online authors and professional aquarists had just as much skepticism for the gallon sps tank. Techniques evolve in time, so will peroxide acceptance, then we can look back in time at where the practice was perfected.

    what's in this thread is the reason I will never have algae, diatom or cyano problems-an easy cheat that permanently removes common aquarium headaches

  25. brandon mason says:

    Peroxide use is well documented on the web in fresh and saltwater tanks, its a decades old practice.

    What we offer in the thread is how to go beyond external treatments to treating a running reef tank without removing items, and we have assembled lists of tolerant and intolerant invertebrate species when in-tank treatments are required.

    This is -not- documented well if you search the topic and as such becomes a new/emerging science in algae/invader control options

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