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El Fab's Simple Guide to Pico Tanks

el fabuloso

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or fab could just edit his first post and have the whole writeup there.




Great Job Fab. I'm going to do my part and keep the Club Pico Thread up to date.



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Part 2 has been edited to include automatic timers to the equipment list.


With the bettacube slowly gaining popularity, it may be worth mentioning as well.

Good point, I'll definitely take that into consideration. I'm only addressing the 2.5–4g range since it's the most popular and easiest setup to put together but I know some people have had great success with the Betta Cube so it might be worth mentioning. Maybe I can do a special article on sub 2g setups? I'll definitely need your help in streamlining that type of setup. :)


Hate to be a pain but I think the Azoo pico tank kit is worth including in the options. You don't see them very often but they're very nice quality and I feel that if more people knew about them they would become more popular.

Good call. I'll be sure to go back and add that on the list as an option.


or fab could just edit his first post and have the whole writeup there.

Since this guide is for everyone I would prefer to leave it open for people to discuss and review as I go along. There's a limit to the amount of information and photos you can put in a post so combining the whole write up into one post will be impossible. I'll do my best to make the different parts easy to follow and jump around.

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Hey Fab one thing you might add is a DIY Battery Powered ATO. These things loose water fast to evap and salinity goes nuts. I built one from plans in the DIY section.



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Part 3: Lighting, Filtration and Flow



Evilc66's 3g pico with LED retrofit.


The lighting you choose determines what you can keep in your tank making it the single most important part of your setup. Most of the lighting options available for nano tanks are also available for pico tanks—with size being the only obvious difference and coping with the effects that certain types of lighting have in such a small space. It's important not to focus so much on watts per gallon and instead concentrate more on what you plan to keep in your tank. If you're a beginner, be sure to read the article on Lighting Options to gain some basic insight on the various types of lighting available in the hobby.



Cong's 3g pico with custom 70W Viper metal halide.


Some people have managed to incorporate metal halides in their pico setups with great success. The main concern with metal halide over a pico is dealing with heat and evaporation. It is for that reason that metal halides are best reserved for more experienced hobbyists who are prepared to deal and address those issues.


Another option for pico tanks that's starting to gain some popularity is LED technology. The benefits of LED lighting is comparable to metal halide but without the heat issues and high power consumption. Because the technology is still in its infancy the initial cost for an LED fixture can be rather high although a custom retrofit can be done easily for anyone willing to take on the challenge.



My 3g pico with 36W power compact lighting.


Power compact (PC) fixtures are the simplest, most common lighting solution for a pico and can sustain a staggering amount of biodiversity. It's extremely important to plan ahead and get a good idea of what you'd like to keep as different types of corals have different light requirements. A majority of soft corals can be sustained by PC bulbs in the low- to mid-range, LPS corals in the mid- to high-level range and up to a certain extent, some SPS corals in the highest end of the PC spectrum.


You may or may not need to upgrade your light depending on which setup you decide to go with and what you intend to keep. However if you plan on setting up a custom AGA tank, you will need to choose an appropriate light fixture right from the start. Let's explore some of the popular PC lighting options for pico tanks in the 2.5–4 gallon range.



18W Coralife Mini Aqualight

The Coralife Mini Aqualight is a sleek fixture that can sustain most soft corals and some LPS. The hood contains two power compact bulbs: one 9W 10000K bulb and one 9W Actinic 03 bulb for 18 watts of combined output.




18W Current Satellite

The Current Satellite is a low-profile fixture that features a 24-hour lighting system. Its energy efficient electronic ballast powers an 18W 10,000K/460nm SunPaq lamp that meets the needs of most pico setups. A built-in lunar light completes the system for convenient nighttime viewing.




36W Current Dual Satellite

Taking the Satellite fixture a step further, the Current Dual Satellite offers the ultimate power compact solution for any pico. It doubles the wattage of the Current Satellite by offering four lamps in two: one 18W dual daylight 6,700K/10,000k SunPaq bulb and one 18W dual actinic 420nm/460nm SunPaq bulb. It has two separate switches so that each lamp (along with the built-in lunar light) can be controlled individually by a timer. This fixture can sustain most LPS corals and even some hardy SPS corals.


TIP: If you're setting up a pico kit, start with the stock lamp and consider upgrading once you start stocking your tank with more light-demanding corals.




In picos, just as in nano tanks, natural filtration is the most effective method with live rock playing a critical biological component in your setup. Live rock forms the backbone of your tank and is the primary source of life support in your system—so it's important that you don't skimp out and try to get the best that's available. Fortunately you won't need that much in a pico so getting the best quality rock won't necessarily break the bank. The general rule of thumb is to use 1–1.5 lbs. of rock per gallon of water so for a 3-gallon pico, anywhere between 3 and 5 lbs. is a good amount. Be sure to leave enough room for corals and other livestock.




TIP: An important thing to remember when it comes to choosing live rock for a pico is to get several pieces instead of one big rock. This will give you a lot more options to work with when it comes to aquascaping as well as the ability to rearrange your rockwork as you start stocking your tank. Read the article on Live Rock Selection to learn about the different types of live rock out there and what you need to look out for.


A protein skimmer is another form of natural filtration that's commonly used in nano tanks but isn't needed in a pico. Skimmers not only remove organic waste from the water but can also include trace elements required by corals and invertebrates and therefore can have adverse effects given a pico's already limited water volume. The best form of nutrient export in a pico is through regular water changes, which in itself also replenishes depleted levels of trace elements.




Another natural means of nutrient export is through the use of macroalgae. Chaetomorpha (commonly referred to as "chaeto" or "cheato") is the best kind to use in a pico as it is easy to cultivate and not as invasive as other types of macroalgae. Chaeto takes in nitrate and phosphate from the water, which it needs in order to grow. The absorbed nutrients are then exported by harvesting the algae on a regular basis.




Chemical filtration removes dissolved wastes with activated carbon being the most common type available. Other adsorbents like Purigen can remove ammonia, nitrite and nitrate while Chemi-Pure Elite goes a step farther by removing silicate, phosphates and other organic particulates. Be aware that some carbons can leach phosphates and that whatever you use, you will need to keep the media clean and replace it regularly to keep it working properly.


Last but not least is mechanical filtration. This process is done easily by trapping suspended debris and detritus from the water using filter pads or floss. A popular and very inexpensive media to use is polyfill stuffing material that can be found in any hobby shop or arts and crafts store.



The same principles used in larger tanks with a sump and fuge can be easily applied in a pico at a much smaller scale.


Finding a good balance between these different processes is important in order to maintain a stable pico. In larger systems these elements are often spread out throughout the tank with a separate sump and fuge to accommodate the required space and materials but incorporating all these things in a pico's limited space can prove to be a difficult task. Some people add a sump to their setup that can sometimes be much larger than the display tank itself. While this type of system ensures stability by providing a pico with immense water volume, it's generally impractical and often defeats the point of setting up a pico in the first place. A canister filter is an obvious solution and although it can be quite effective, it can also backfire and work against you if not maintained properly so it's best to avoid them in a pico setup if at all possible. A popular and effective solution is to modify a hang on back (HOB) filter into a mini fuge with AquaClear models being the most common and efficient type to use. People with an AGA setup have the added benefit of using this method as well as having the option of customizing their tank by constructing a built-in fuge. In the next installment we'll go over some of the basic steps and options for modifying an AquaClear filter for that purpose, given its efficiency and ubiquity among pico tanks in the 2.5–4g range.




Circulation and flow form the third important component in the pico setup. Proper water movement goes a long way toward helping a reef system thrive and picos are no exceptions. Water currents help transport and mobilize food, oxygen and nutrients, as well as carry away waste products. In addition to providing essential nutrients and being instrumental in waste removal, water movement also influences:

  • growth of corals
  • the formation of new coral colonies
  • growth of problematic algae
  • the overall health and well-being of invertebrates



The rule of thumb is to provide 10–20 times the total water volume of the tank but just like with lighting, it's more important to plan ahead and assess what you expect to keep in your tank as certain types of corals have specific requirements. Generally speaking though, the more flow there is in the tank, the better. The stock filter that come with the pico kits are typically underpowered which can cause increased growth of nuisance algae so it's always a good idea to supplement your setup with a decent powerhead. Again because space is limited in a pico, your choice is somewhat limited although some of the most commonly used powerheads like the Rio 50 and the Mini-Jet 404 are great at providing the recommended flow and are just the right size for most picos. The AquaClear fuge mod is another great way to increase water circulation in a pico and by itself can be enough for most setups.

TIP: Where you place the powerhead in your tank is equally important as the amount of flow it provides. The location of the powerhead along with your rockwork can dictate coral placement. It's also a good idea to allow the powerhead to break the water's surface for better gas exchange.



We've covered some really important components in this part that will help tremendously with the overall health and success of your pico. Keep in mind though that while these components are beneficial, they are NOT necessary to start a pico tank (unless you're starting with an AGA setup) so don't feel pressured to upgrade right away. Plan ahead and plan carefully and the rest should play itself out.



Part 4: Modding An AquaClear Fuge

Edited by el fabuloso
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Part 3 is finally posted. Wow—that was a lot of information to cover and condense! I did my best to sort it all out and I hope it's simple enough to follow. I know some of the information on it might be open to debate so feel free to post any objections and recommendations you might have.


Also, I only listed the three commonly used light fixtures that I know off the top of my head. If I've left out any good ones, let me know and I'll update the list to include them.


Hey Fab one thing you might add is a DIY Battery Powered ATO. These things loose water fast to evap and salinity goes nuts. I built one from plans in the DIY section.

Good call. I will definitely cover evaporation and ATOs in its own section. I know there are some good techniques out there (battery operated, gravity-fed, etc.) but it's important that they be streamlined for the simplicity of this thread. I would like for anyone with some info on a good build to PM me with details so I can start outlining that section.

Edited by el fabuloso
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This is so neat!! I'm gonna start a pico soon, I already have a 25g and this is the info that I need for the pico. It's really cool what you are doing Fab very very helpful thanks alot, I'll definetly be coming back. I got an AGA cube last night it measures 10" high and 9" L and W. I want to keep zoa's only and some sexy shrimp ( if I can put them in a tank this size? How many?). I'm strongly inclined to use the coralife mini as it would sit perfectly on top, I would love to use the 36w satellite but it does'nt come smaller then 12" long. My question is, is the light (mini) enough for zoa's and some mushrooms? what other kind of coral can I keep under this light? I would really appriciate your expert advice. Thanks alot for your reply.

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That AGA cube will make a sweet pico. You should be able to keep most softies and some LPS (blastos and candy canes) with the Coralife Mini including zoas. Sexy shrimps are perfect for picos and you could do 3 or 5 in a tank that size. Good to know you find this thread helpful. :happy:

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Good point, I'll definitely take that into consideration. I'm only addressing the 2.5–4g range since it's the most popular and easiest setup to put together but I know some people have had great success with the Betta Cube so it might be worth mentioning. Maybe I can do a special article on sub 2g setups? I'll definitely need your help in streamlining that type of setup. :)

True, good call. Smaller than 2.5g is even a different realm from picos. For the most part it is basically the same- you get a heater and some form of flow with live rock as the main filtration. The coralife 50/50 screw-in bulbs are great for little tanks on a budget ime. The biggest difference I guess is just that they generally need more attention than larger picos. brandonm would probably be of more help, however, seeing as he has done some crazy things with little tanks. I'm ashamed to say it, but my 1.25g pico is doing better than my 10g with fuge ;)

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Yes, it has three separate power cords one for each of the PC bulbs and the moonlight. There are also individual switches for actinic and daylight so you can manually turn them off and on.

Edited by el fabuloso
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Sweet, I first saw that there were separate switches, but I know there are some lights out there with separate switches all powered from one cord, thus making it a virtually unadjustable mess...at least as far as automating, that is...

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Part 4: Modding An AquaClear Fuge



The simple design of an AquaClear filter makes it easy to modify as a fuge.


So far we've established the importance of stability in a pico tank be it temperature, salinity or overall water quality. Adding a large sump to a pico can be bulky and impractical so most pico owners use an AquaClear filter to use as a fuge instead. AquaClear filters are commonly used due to their large capacity and simple design, which makes modifying them fairly easy. A well-built AquaClear fuge keeps a pico tank stable by providing extra water volume, optimal flow, and provides additional space for various filter media and equipment.



The two most popular models for this mod are the AquaClear 50 and 70, the latter being the largest model that can be used for picos in the 2.5 to 4-gallon range. While the basic plan is the same for all, some minor tweaks can be done to adjust the layout and reduce the flow depending on your preference and needs. In this tutorial we'll use an AC70 filter although the same process can be done to any of the other AquaClear models. This guide will also attempt to be as resourceful and efficient as possible by utilizing all the parts that come with the filter.



  • AquaClear filter
  • Aquarium sealant
  • Masking tape
  • Scissors
  • Serrated knife or a small saw
  • X-Acto knife
  • Toothpick


Inspect the package and make sure that all items are present and check for any cracks or damages





Cut the media basket into three pieces
. The media basket is designed to hold the filer media and has three distinct parts. You will need scissors to cut them into three different pieces at the seams.





Take the bottom part of the media basket and place it over the overflow to assess placement
. The bottom part of the media basket will serve as an overflow screen and will help contain everything in the filter. Decide how much room you want for the refugium but leave enough room for other materials and equipment.




Cut a notch on the bottom ridge of the screen using an X-Acto knife




Repeat on the opposite side and make sure the two notches are parallel.




These notches will help support the divider perpendicularly.


Put in the overflow screen and the divider to see how they fit




Assess how high you want the screen to rise above the overflow. Keep in mind that if you set it too low, chaeto and other materials will be able to spill over the display tank so it's best to keep it fairly high but not too high that it impedes the flow.


Insert the divider so that it is perpendicular to the overflow screen by sliding it through the notches
. You should be able to put these two pieces in without glue.




If you notice a lot of bowing on the backside of the filter then the notches aren't big enough and you will need to adjust them. Observe the setup from all angles before gluing everything down and make sure you're happy with the size of the chambers.




Apply aquarium sealant on the sides and the bottom portion of the front part of the overflow screen
. Position and press firmly into place.




Once the overflow screen is in place, add more sealant on the sides and the bottom portion to seal the piece in




Use a toothpick to push the sealant into the grid work.




Give the piece some time to dry.


In the meantime you can modify the intake tube
. The intake tube is way too long for most pico setups so you will need to trim down the part of the "U" tube that goes in the tank. Use masking tape and tape off about an inch to an inch and half area from the top corner of the tube. Use a serrated knife or a small saw to trim off the piece following the edge of the tape.




Take off the tape and rinse everything off
. Snap the intake tube into the modified "U" tube.




Make additional adjustments including optional steps that help reduce the flow of the filter
. A quick and simple one is to cut off the tab on the impeller cover. This will allow the intake tube to turn all the way to the right to decrease the flow even more.




Another common technique to decrease the flow is to clip the impeller blades or to use an impeller from a smaller model. While certainly effective, this requires the additional purchase of an impeller.




Take the divider piece and cut off the top
. Slide the piece through the notches on the overflow screen with the smooth surface facing the fuge chamber. This will help prevent chaeto from getting tangled and snagging into the tabs.




Glue the joints with aquarium sealant
. Make sure the overflow screen is completely dry before doing this step.





Do a water test once the sealant is completely dry
. Check for leaks and make sure everything runs smoothly.




You have the option of using the second divider depending on what you plan to put into your chambers. It can be placed diagonally with a spot to hold the heater creating a sub-compartment for filter floss or whatever mechanical filter media you want to use.




You can place the chemical filter right along the intake tube or in the first chamber. It all depends on your personal preference and how much room you have to work with.


Install lighting
. You will need to provide the fuge with lighting for chaeto to grow. If you're starting with a pico kit, the stock light that comes with the kit will make an excellent light for the fuge or you can use any small PC lamp. Position the fixture carefully so that the light doesn't bleed into the display tank. Maintaining the fuge on a reverse photoperiod helps prevent pH swings and keeps the light from competing with the display tank during the day.






One of the first things people notice is the increased flow the fuge adds to their setup; so much so that it's one of the most common complaints people have. Keep in mind that over time the flow will decrease as it becomes bogged down with organic materials and debris so it's important to keep it clean on a regular basis.


As the fuge matures it literally becomes a fully functioning refugium harboring a variety of microfauna of its own. Pods, worms, lost corals and other filter feeders can be found in the fuge over time. Various types of algae begin to grow especially on the overflow screen and can work like a mini algae turf scrubber by absorbing nutrients and providing food to the tank.







1. The object of the horizontal chambers isn't necessarily to keep stuff from touching each other but as a way to keep things organize so that it's easy to clean and change out the different types of filter media.


2. Adjust the leveling device to make sure the fuge is perfectly level at all times to prevent water from spilling.


3. Be sure to compensate for the added water volume. An AC70 fuge can add up to half a gallon of water to your tank. In the event of a power failure or should you need to unplug the filter, all the water in the fuge will be flushed back into the display tank and can cause the tank to overflow if the water level is too high. A good way to prevent this is to fill your tank up to its maximum capacity before powering up the filter. Mark a line once the fuge is up and running and avoid topping off above that line.


4. The use of live rock rubble in the fuge is a hotly debated topic. Because the majority of the biological filtration takes place deep within the live rock pieces in the display tank, the benefits of live rock rubble are somewhat negligible especially with what little pieces you end up using. With that, some people insist on adding live rock rubble to their fuge, which ultimately comes down to personal choice. If you do decide to use live rock rubble in your fuge just make sure to clean them out regularly during maintenance as the trapped debris and detritus can easily release nitrates back into the tank.


Part 5: Setting Up Your Pico

Edited by el fabuloso
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