Can Two Canister Filters Be Used In One Fish Tank?

Canister filters are renowned to be the most efficient fish tank filters around today. Yes, they may be expensive but if you can afford to install one, they will save you a whole lot in terms of time spent maintaining them and of course money. But for those who already have a canister filter in their aquarium, the next question that always comes to mind is should they now install two filters and will this be beneficial to the overall filtration of the fish tank water?

Actually, this is a matter of preference that most fish breeders cannot agree on whether it is a good idea or not to have two canister filters in one tank. That question has been argued about since canister filters were invented.

Rather than taking a side, I will instead talk about what happens when you have two canister filters in one aquarium and it will be up to you to decide which you choose.

The Benefits Of Having Two Canister Filters.

The main reason most people give for having to filters is back up. That is to say that when one filter breaks down, you will still have a backup filter to ensure that the water in your aquarium still remains healthy. This would be a good reason especially if you live far from a good pet store and won't be able to repair the faulty filter quick enough.

The other reason for having an additional filter is how big the tank is. Supporters to multiple filters argue that if the fish tank is too large, filtration done by one canister filter will not sufficiently purify the entire tank as there will be blind spots where the water will not be drawn into the filter. With two canister filters and proper positioning of the separate inlets, these blind spots will not exist.

What's The Downside Of Using Two Canister Filters

The main issue about having multiple canister filters is water movement. The movement of water in the aquarium affects the exchange of oxygen and carbon dioxide. The faster the rate at which water moves, the faster the exchange will be thus reducing the amount of CO2 in the tank. But isn't this supposed to be good? Well, not if you also have aquatic plant life. Plants use CO2 and give out O2. By doing so, plants actually help maintain a healthy balance of CO2/O2 levels in the water. Having insufficient carbon dioxide levels will stunt the plants growth and cause them to lose their luster.

Too much filtering will also remove the important nutrients that plants need, along with other waste matter. It is actually true that in a tank with plants, it is the plants that provide a better and more efficient biological filtration than the beneficial bacteria.

Finally, too much water movement actually has an adverse effect on the fish as well, especially fish that are more used to very little water movement. The faster water movement that an additional filter makes will cause them unnecessary stress and might even prevent them from breeding properly.

These are the advantages and disadvantages of setting up two canister filters in one fish tank. If you do plan to install an additional filter, just remember to reduce their suction rates to counter balance the disadvantages.