What Is An All In One (AIO) Aquarium? Great For Your First Tank!

Over the years I have set up many All-In-One Aquariums for clients with great success. For a beginner to this fantastic hobby, they are the perfect way to try your hand at saltwater without spending too much money.

The technology that has progressed for these type of aquariums over the last 10 years has really enabled you to keep any coral and fish in an AIO aquarium (Providing the aquarium is big enough and mature enough to house them).

An AIO Aquarium is an aquarium that has the filtration installed behind the back glass of the tank. The water flows in through an overflow, gets filtered, heated, then pumped back into the tank. They offer compact, affordable, and easy to maintain solutions that are perfect for beginner aquarists.

So why doesn’t everyone have an AIO aquarium? There are a few drawbacks to this type of aquarium which you can find out about in this article.

What Is The Point Of An AIO Aquarium?

The main points to an AIO aquarium are simplicity and cost.

Setting up a saltwater aquarium can become very expensive, very fast and this deters many people from trying this hobby. A way to combat this has been the development of the AIO by several aquarium manufacturers, with great results!

AIO Filter Section Behind Back Wall
AIO Aquarium Filter Compartment
Typical 3 Compartment Layout

An AIO aquarium houses everything together and usually will come as a complete kit or with recommended products to set up a great little reef tank.

With most of the popular AIO aquariums being smaller, nano (under 30 gallons) the cost to maintain the aquarium is low and the maintenance is simple. This gives the new owner the best chance to find out just how addictive it is to have a piece of the world’s ocean sitting next to your couch!

How Do AIO Aquariums Work?

The filtration area is added behind the back wall of the aquarium. It is usually segmented into several compartments with the water flowing from one end to the other, before returning back into the tank area.

Each stage is designed for a specific purpose and there are multiple ways in which manufacturers layout these stages.

A typical arrangement is as follows:

Stage #1 – Surface Skimmer

Typical AIO Overflow

This is where the water drains from the main tank into the filtration section. Most AIO aquariums will have a toothed grid that allows the water to flow into the filter section while keeping out the critters.

Stage #2 – Mechanical Filtration

Filter Sponge On Right

This compartment is directly behind the overflow and contains some kind of sock, floss or sponge to act as the main mechanical filter.

The job of the mechanical filter is to remove the large debris and particle matter from the water. Uneaten food and fish poo are the usual items collected by the mechanical filter.

This filter needs to be rinsed or replaced every couple of days.

Stage #3 – Protein Skimmer

Tunze 9001 Is A Popular Skimmer Upgrade

This area houses the protein skimmer and is the first filter device the water will be exposed to as it leaves the mechanical filter stage. The microscopic dissolved organic compounds within the water are now removed by the protein skimmer.

Most aquarists will upgrade this piece of equipment as their tank matures and they wish to keep a higher bioload (more inhabitants) in their tank.

Stage #4 – Chemical/Biological Filtration

InTank Media Rack Upgrade

Most All-In-One aquariums will utilize a ‘Media Rack’ of some kind to stack the different types of filter media on top of one another while allowing for water to easily flow through them.

Ceramic Spheres, Activated Carbon, Granular Ferric Oxide & Bio Pellets are all common filtration media. Most aquarists upgrade to using Purigen or ChemiPure Elite in AIO’s because they combine a lot of the above media into a single packet which lasts months.

To find out more about the specific types of filter media and what they do head over to my article
Types of Aquarium Filter Media & What They Do“.

Stage #5 – Return Section

AIO Aquarium Filter Compartment
Return Pump & Heater Section

This area houses the return pump to deliver the water back into the aquarium at high pressure. This helps to create flow in the aquarium and prevent ‘Dead-Spots’.

This section is also where the Heater and Automatic Top-Off System are usually placed. The automatic top-off is a device that replaces fresh water lost to evaporation.

To find out more about the Automatic Top-Off system please read my article
What Is An Aquarium Auto Top Off?“.

Here is a great video detailing a typical AIO Aquarium:

What Size Do AIO Aquarium’s Go Up To?

Generally, the All-In-One aquariums have been limited to the smaller to mid-size aquariums. This is mainly due to the physical size and number of devices needed to run, maintain and clean the larger aquariums. These would not be able to neatly fit in the back compartment.

The larger filtration equipment is usually hidden away in a sump under the stand/cabinet in other types of aquarium.

The nice part about the AIO aquariums is they try and keep all the equipment hidden out of sight to allow the beautiful inhabitants of the aquarium draw the eye rather than the ugly devices.

Here is a list of popular AIO aquariums and sizes:

AquariumVolume Sizes – Gallons
JBJ Flat Panel25, 45, 65
JBJ Nano Cube20
Waterbox Cube10, 20
Waterbox Marine AIO28, 30, 40, 50
Fluval Sea Evo XII13.5
Coralife Biocube16, 32
Redsea Max Nano20
Redsea Max E Series45, 56
Innovative Marine Fusion Pro10, 14, 20 ,30, 40
Innovative Marine Lagoon25, 50
Innovative Marine Shallow Reef60, 80

Are AIO Aquariums Easy To Keep?

Yes! They have been designed to make maintenance very easy and with a few upgrades you can easily keep an impressive reef aquarium. Just like any saltwater aquarium, setting up a regular maintenance routine will help to keep your tank in pristine condition.

RedSea Max E-Series AIO Aquariums

Regular water changes and the use of a media rack to easily remove and replace your filter media will keep your filtration working at its most efficient.

Most people joining this hobby with no experience usually being with an AIO aquarium because of the many stores that offer them in a complete kit. Just put it all together, add the water and let it cycle. It is very easy to do! I know many successful reefers who ‘Cut Their Teeth’ on an AIO aquarium and now have +200G reef tanks! They work!

Are There Downsides To AIO Aquariums?

As good as the AIO aquariums are they do have a few downsides:

  1. You are limited to the equipment you can add to an AIO. There is not a lot of room to add additional devices. Some tanks may need to be modified to run a chiller for instance.
  2. There is not as big a selection of certain equipment from the big manufacturers, compared to running a sump-type aquarium.
  3. Smaller aquariums can have large temperature, Ph, salinity and other parameter swings because of their low water volume.
  4. A lot of the standard filtration equipment that comes with the ‘bundles’ seem to be soon upgraded by the owners.
  5. The larger AIO aquariums can be quite expensive.

Even though there are a few downsides, for getting into the saltwater hobby the AIO aquariums are a great first step and one I recommend to anyone first wanting to try keeping a reef tank.

5 Awesome AIO Aquarium Setup Examples

Fluval Sea Evo XII 13.5 Gallon

Fluval Sea Evo XII Large

Ready To Go Cost Approx $300.00

NUVO Fusion 14 Gallon Peninsula Pro

Nuvo Fusion 14

Ready To Go Cost Approx $650.00

Redsea Max Nano 20 Gallon

Ready To Go Cost Approx $1150.00

Coralife Biocube 32 Gallon

Ready To Go Cost Approx $810.00

Waterbox Flat Panel Rimless 65 Gallon

Ready To Go Cost Approx $2160.00

Further Reading

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Hi, I'm Richard and I have been an avid aquarist for over 30 years with a passion for Saltwater Aquariums. I love to pass on my knowledge to help others get the same amount a pleasure out of this hobby as I do. View my About Me page to find out more about me & my mixed reef aquarium.

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