How To Setup A Nano Tank

A nano tank is any saltwater aquarium that is smaller than 15 gallons.

Some hobbyists, perhaps in an attempt to push the envelope, have even gone with aquariums that are 5 gallons or less. These are sometimes referred to as ‘pico’ tanks.


10 Gallon Acrylic Nano Tank

In my opinion, nano and pico tanks are best used to display hardy zoanthids, star polyps, small leathers or mushroom colonies, along with crustaceans such as hermit crabs or shrimp.

Unless quarantining a new fish or medicating a sick fish, I prefer not to keep saltwater fish on permanent display in a saltwater tank that is less than 15 gallons.

I personally feel that if you want to keep one or two small marine fish, the tank should be at least 30 gallons. And this only for certain species of fish that do not grow to more than 2 to 3 inches in length.

Choosing A Nano Tank

Tanks originally designed for freshwater use are often used as saltwater nano aquariums. It is also not uncommon for small tanks that were previously used as freshwater aquariums, to be ‘recycled’ and transformed into nano reef aquariums.

Because we will be placing a few pounds of live rock and sand, along with heavy saltwater into our nano tank, we should choose a tank with glass that is at least 6mm thick. This minimum glass thickness also ensures that the silicon bond at the seams will be strong enough.

Acrylic tanks are another option and they make for very strong saltwater nano tanks. Good quality acrylic is also clearer than glass, but since acrylic scratches very easily, special care must be taken when cleaning the panels once the tank is up and running. A weekly gentle scraping of any algae on the glass with the edge of an old credit card always does the trick!

Nano tanks are also available with a bowed front panel with seamless front corners which creates a perception of greater depth from the front of the tank to the back.

How To Calculate Your Nano Aquarium’s Water Volume Based On Tank Dimensions

To calculate the water volume of your aquarium multiply the length, width and height in inches and divide that number by 231.

An aquarium that is 20″ (L) x 10″ (W) x 12″ (H) for example is 10 gallons.

Canopy Or Open Top?

If you don’t plan on keeping any fish in your nano tank, a canopy or cover will not be essential. Indeed, open top tanks will be easier to keep cool with a small fan.

If you plan to keep a fish or two (as mentioned earlier, this is ill-advised in any tank that is less than 30 gallons), then having a cover over your nano tank is a must. Fish do get skittish and occasionally jump out of uncovered tanks, nano or otherwise.

Nano Tank Lighting

If the nano tank you choose comes with an in-built lighting fixture in the canopy, bear in mind that such a fixture is not easily modified should you want to upgrade the lighting so it can support photosynthetic corals — the ballast will need to be replaced if you are upgrading to T5 HO or power compacts, and the internal mounting reconfigured to accommodate the new type of light and ballasts.

Unless you are particularly handy with electrical re-wiring and enjoy DIY projects of this type, you’re better off going with LED lighting that usually come with external ballasts that do not need to be mounted into the canopy.

The added benefit of LED aquarium lighting is that they transfer almost no heat to the water while still being in the spectrum and intensity that can support corals.

10 gallon nano tank

LED Lighting On Nano Tank

If you choose to go with an open-top nano tank, there are many clamp-on LED lighting fixtures available today that will do the job of providing adequate lighting for corals.

Protein Skimming The Nano Tank?

You will not need a protein skimmer for your nano tank if you are committed to doing small water changes every 3 or 4 weeks for a simple coral-only tank, or every week if you are keeping a fish in your nano tank. A 10% water change in a 10 gallon nano tank equates to only 1 gallon of new saltwater!

The other reason for foregoing a protein skimmer on you nano tank in favor of regular water changes is that a skimmer would simply take up too much space in your tank. And let’s face it, if your protein skimmer is managing to skim gunk out of your nano tank, a water change is long overdue.

That being said, I would choose to install a suitably-rated protein skimmer on any tank that is over 30 gallons.

Basic Nano Tank Filtration

You can successfully run a nano tank with a simple hang-on-back (HOB) filter. As long as there are separate compartments in the HOB filter for activated carbon and sponges for biological filtration, you are good to go.

When choosing a HOB filter, make sure that each compartment can be accessed easily so that you can change or add media in one compartment without disturbing the other media too much.

Perhaps one of the major drawbacks of hang-on-back filters is that in the event of a power outage, most of the water in the filter will drain out into the tank. When the power comes back on again, the filter will need to be primed again, meaning that you will need to scoop water from the tank with a cup and pour some of it back into the media compartment of the filter to get it running again. If the filter is not primed again, it will run dry and burn out the pump.

Also, if left dry for too long, the biological media will also experience a die-off of nitrifying and denitrifying bacteria, compromising the bio-filter of the tank. Another reason to not keep fish in a nano tank!

Live Rock And Sand In A Nano Tank

I’ve never been a fan of bare-bottom tanks, so I usually add an inch or two of fine sand before stacking a few pieces of live rock on top.
Chose a few pieces of the most interesting looking live rock you can find — personally, I always look for pieces with nice coralline algae growing on them.

As to how much live rock to put in your nano tank, use your discretion and personal taste — you don’t want to crowd your nano tank with too much live rock, but at the same time you don’t want to use too little as live rock forms a valuable part of your tank’s bio-filter.

Two pounds of live rock per 10 gallons is a good starting point, although it would also depend on how porous the live rock is.

Depending on where the rock originated from, some larger pieces can weigh less than some smaller pieces.

And be patient with cycling your new nano tank before adding any livestock!

Nano Tank Water Parameters

As discussed on our pages on Water Parameters in your new nano tank should be as close to ideal as possible.

One thing to bear in mind is that water parameters in nano tanks, temperature in particular, will be prone to large fluctuations. For this reason, nano tanks are best set up in environments where the temperature is relatively consistent, day or night.

Nano tanks can be cooled quickly by installing a small cooling fanto blow across the surface of the water. Such evaporative cooling will require dilligent daily top-ups with DI/RO water. You’ll be surprised how much the water level in a nano tank can drop if left alone for 2 or 3 days with a cooling fan blowing across it. Be aware that the salinity in a nano tank can swing out of the desired range if water is not regularly topped up.

It is also very important that you do not overfeed your nano tank. Food that is not consumed by fish or coral decomposes into poisonous ammonia very rapidly in the small confines and limited bio-filtration capability of the nano tank.

Read More About:

Why Beginning Hobbyists Should Avoid Starting A Nano Aquarium

Ideal Water Parameters For A Reef Aquarium

Activated Carbon

Live Rock


LED Aquarium Lighting

Cooling Fans



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