Last Updated on April 23, 2023 by Coral Realm

Fluval is a very well known brand, producing brilliant aquarium heaters, fish food, water conditioners, and fish tanks. The Fluval Spec Series of fish tanks are well-loved, but this article will focus on the Fluval Evo 13.5 Aquarium Kit. This aquarium kit is designed specially for saltwater setups, and to promote coral growth. 

There are two different Fluval Sea Evo Aquarium Kit sizes available; 5 gallons and 13.5 gallons. Both of these models offer built-in filtration hidden in the honeycomb back aquarium and LED lighting found in the hood. It is a brilliant option if you want the laborious process of finding decent accessories cut out. The 5 gallon model is on our list of the best 5 gallon fish tanks.

In this Fluval Evo 13.5 review we will look at the design of the fish tank, the filtration, lighting, and the accessories that it can accommodate. 


Fluval Sea Evo Design

The design of the Fluval Sea Evo Saltwater Aquarium Kit is very sleek and modern. Honeycomb trim hides the back compartment which houses the filtration system while not looking out of place at all in a modern aquarium. More honeycomb trim is found at the top of the tank, which hides the waterline. 

The design also allows for viewing from three angles. Both of the longer sides and one shorter edge are completely clear for uninterrupted views. This allows you to have more setup options, as you can set up the Fluval Sea Evo on a table, stand, or worktop. As long as the filter compartment is against a wall and near a power socket, you will have a brilliant viewing experience of your tank. 

The 5 gallon Fluval Sea Evo measures 20.5 inches in length, 11.6 inches in width, and 7.5 inches in height, while the Fluval Sea Evo 13.5 gallon measures 23.4″ x 11.5″ x 15.6″. 

Fluval Evo 13.5 Filtration

Fluval Evo 13.5 Filtration

As we have mentioned previously, there is no need for an external filtration system. The Fluval Evo 13.5 comes equipped with a filtration system built-in. This system can be found in the back compartment which is hidden by the honeycomb design. 

Inbuilt filtration systems are sometimes very light on the actual filtration. However this is what the Fluval Sea Evo does very well. 

Full triple stage filtration is supplied. A foam filter block with a handle to easily remove it for cleaning is the mechanical media and works to remove the large pieces of floating debris from the water column. Biological filtration is supplied with the BioMax insert. This provides a perfect place for beneficial bacteria to colonize. These bacteria form part of the nitrogen cycle, and work to remove dangerous nitrogenous compounds ammonia, nitrite, and nitrate from the tank. An activated carbon insert completes the triple stage filtration. Activated carbon removes impurities such as odors, discolorations, and contaminants such as chlorine. 

Having these three stages of filtration come as standard with both the Fluval Evo 13.5 and the 5 gallon tank means that you can get your aquarium set up immediately, and then you can start cycling the tank. Cycling the tank is incredibly important. Essentially it is letting the bacterial colonies form in the biological filter and substrate. An aquarium bacteria supplement such as API Quick Start can greatly reduce the time.this process takes.  

By adding live rock into the tank, not only will the fish have a natural formation, but it will aid in biological filtration as well.

The pump output for the 5 gallon tank is 55-80 gallons per hour, while the Fluval Evo 13.5 has a pump output of 132 GPH.


The lighting is a real plus point in the Fluval Sea Evo. Both sized models have built in LED lighting which is designed to promote coral growth. Being designed specifically for marine setups, this allows for you to choose any coral available, both LPS and SPS coral

The Fluval Evo 13.5 has 31 individual LEDs, while the Fluval Sea Evo 5 gallon has 37 individual LEDs. This doesn’t mean that the Evo 13.5 has less powerful lighting however. The Fluval Evo 13.5 produces 1383 lumens, with a color temperature of 14,000 K, while the 5 gallon produces 759 lumens with a color temperature of 11,000 K. 

As we have said, the lights in both of these tanks provide optimal conditions for coral growth. Corals will look brighter, their colors being optimized by the lighting temperature. 

The LED lighting also has a convenient touch start feature. This touch start feature allows for a one touch start of either daytime or nighttime lighting. 


What is brilliant is that Fluval has kept in mind that for a saltwater tank there are essential extras that need to be installed. The Fluval Sea Evo is designed so that the Fluval Submersible Heater and the Fluval Sea Protein Skimmer can both fit with the hidden back compartment. This helps to keep the tank itself free of unnecessary eyesores. Having the protein skimmer housed in the filtration compartment is brilliant!

Having the heater hidden in the back compartment also has another useful function; it prevents any hot spots forming in the tank. As the water flows over the filtration media and over the heater it is pumped back into the tank. This constant water flow over the heater means that the heat produced by the heater is distributed evenly. This is exactly what you need for a successful reef tank. Both saltwater reef fish and corals need a stable temperature, and having the heater in a place of high water flow helps to ensure this.

The tank interior will also accommodate a Fluval CP1 or Fluval CP2 circulation pump. These pumps are wave makers, which increase water circulation throughout the tank, much like a powerhead.


The major downside to both the Fluval Sea Evo fish tanks is the small size. Marine reef tanks are usually much larger than the 5 or 13.5 gallons on offer, as reef fish in the main need more space than will be offered from these tanks. 

However this isn’t to say that you cannot keep any reef fish at all. Gobies are amazingly colorful small fish, and can be housed in small tanks. Also keeping corals, anemones, and other benthic invertebrates is an incredibly rewarding experience in itself. 

Always do careful research when looking to stock a fish tank,  but especially trying to stock a smaller tank where space is already at a premium. Don’t overstock, as not only will fish most likely become aggressive over territory, but the filter will have to work on overtime as well. Our article on the best nano reef fish will help point you in the right direction.


Hopefully this article has given you the information that you were looking for on the Fluval Evo 13.5 gallon saltwater tank, and the Fluval Sea Evo 5 gallon tank. 

In short, the Fluval Evo 13.5 is a brilliant way to get started on your marine reef tank journey. It has everything that will enable you to successfully keep corals and small reef fish, without any of the hassle that a larger reef tank will bring. A brilliant starter tank which will build your confidence in keeping reef organisms, and you’ll soon find yourself wanting a larger reef tank!

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Coral Realm

1 Comment

  • When you say “Both saltwater reef fish and corals need a stable temperature”, how do you account for things like rain in the real world?

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