Two Cannister Filters in a Single Tank? Is that Really Absurd?

Updated: Oct 6

The typical rule of thumb when it comes to optimal filter recommendations for an aquarium is typically the following:

  1. Use an external cannister filter with multiple chambers for both mechanical and biological filtration.

  2. Acquire a filter that has a flow rate between 3-5x the amount of water within your tank.

Both of these recommendations are consistent with what we also believe, but we make three extra recommendations to ensure a filtration strategy that will keep your fish and plants healthier and living longer while effectively controlling algae, disease, and maintaining the showroom level aesthetic.


Pro Tip 1: Use Two Cannister Filters


Particularly for planted tanks that are 40 gallons or larger, two filters should be the default set up. Having two filters offers extreme flexibility to tune media and adjust flow rates for aquarium life specifications. Along with this flexibility, a two filter setup has the following top benefits:








  • Eliminates 'Dead' Zones. One of the most common reasons that algae begins growing in a planted tank are the 'dead' zones where water movement does no exist. These areas may be due to the lack of water power coming from the outflow or natural obstructions such as plants, rocks, or wood. By setting up 2 independent filters with one near the front of the tank and the other near the rear, the aquarium maintains a consistent circular flow to ensure all of the water is properly filtered. Eliminating 'dead' zones is the top benefit of a two filter system strategy


  • Eliminate Risk of Complete Filter Failure. The second biggest benefit of a two cannister filter system is the failover redundancy that a two filter system creates. Whether you actively take a filter off-line for maintenance or an unplanned failure occurs, the aquarium still has an additional filter to fall back on. You have likely invested thousands and may have creatures and plants that you love, eliminating risks that they may die or deteriorate should be a priority.


  • Added Water Volume for Stability. The last top benefit is the added water volume within the filter itself. Why the water contained in the cannister filter is small relative to the aquarium, it will still aid in water stability. When conducting water changes or experiencing loss through evaporation, an aquarium's water parameters will de-stabilize which may lead to fish, shrimp, and plant death. Deploying a second filter adds additional water volume to minimize the effects of this de-stabilization process, reducing the risks to your aquatic life.


Pro Tip 2: Use a Surface Skimmer Glass Inflow



Surface Skimmer + Traditional Inflow



Deploying a two filter systems gives you flexibility to filter both the bottom and top layer of aquarium water. To accomplish this goal we recommend pairing a traditional inflow with one that has a surface skimmer option. A single surface skimmer inflow eliminates surface scum, keeps the aesthetic look of the aquarium without requiring a separate surface skimming filter.





Pro Tip 3: Compliment the Filters with a Clean Reactor




Finally, an essential addition to ensure that your filters perform optimally is to use them in conjunction with a 'clean' reactor. Twinstar Sterilizers such as the Twinstar Nano and Yotta have several benefits that ensure a healthy and clean aquarium for your aquatic life.






  • Eliminate green algae spores without negatively impacting beneficial bacteria. When algae spores begin propagating within the aquarium those spores will ultimately end-up in your filter system and persist. This leads to higher than normal filter maintenance and larger water exchange which could lead to de-stabilization. Using a Twinstar Sterilizers prevents this from occurring by reducing the amount of excess nutrients within the aquarium. The sterilizer ensures an environment where plants can thrive.


  • Prevent mold and pathogens in the air from depositing themselves into the aquarium. Unfortunately, pathogens from the air above your aquarium do exist and do make it into the aquarium. Most don't realize that this occurrence is common and leads to disease and other problems. While filters prevent build-up of debris, waste, and excess food that is left by the aquatic life, they do not prevent these pathogens from proliferating. The combination of a sterilizer with the cannister filters make for a multi-layered protection system that will keep the aquarium safe.

Through our years of testing and maintaining nature aquariums our two cannister systems, surface skimmer attachment, and Twinstar sterilizer combinations provide the ideal filter strategy to make aquascaping as easy as possible. Finally, you can find all of the equipment you need in our online or new brick-and-mortar store. We can even help you create, build, and maintain your aquascape if needed. Simply check out one of our service plans or schedule a consultation.


Happy Aquascaping!