Yes, you can put two filters in a fish tank, and in many ways, this can be very beneficial to the fish in your tank. However, there are also a number of considerations you need to keep in mind before doing it.
It is not as simple as just adding a second filter and having an even cleaner tank. In fact, a second filter can prove to be quite complicated.
Having a second filter is often known as redundant filtration. The idea is that there is a second filter that does not really do any of the work. However, it is there as a backup. By this, we mean that this second filter will kick in if your main filter was to fail or break.
This method is often used in more established tanks. It can offer you peace of mind, especially if your tank is well established with a good bacteria colony.
Having a spare one will make sure all is not lost, as both of the filtration systems will be able to establish their own bacteria colony, meaning you always have one to fall back on should the other go bust.
This is especially handy in situations where you may need one new filter. Introducing a new filter into an already established tank can be tricky and time-consuming.
If you already have a working spare that is used to the conditions of the tank, you can just rely on this until the new one is established. This also poses less of a risk to the delicate conditions in your tank.
However, there are also downsides that you need to consider, too. Bear in mind that new tanks may just need one filter, to begin with, as you will need to build up the bacteria colonies and establish the pH levels within your tank first.
You may also want to bear in mind the fact that it is often the bigger tanks that will benefit from two filters.
Smaller tanks may struggle with two filters thanks to the increased water flow created. This can have a knock-on effect on your tank life who may not be able to cope with these new conditions.
Another thing to keep in mind is that having two filters actually increases your workload when it comes to cleaning and maintaining them.
Sure, you may have to clean them less, as two of them will be doing the job, but the fact still stands that when you do need to clean them you will have to do the process twice over.
You will also still need to clean your tank regularly, as well as keeping up with water changes. Just because you have an extra filter, does not mean you can get away with less cleaning.
Can you over filter a fish tank?
No, you cannot really over filter a tank. However, there are some exceptions. Exceptions would include if you have a small tank or have creatures that struggle with too much water flow. In this situation, too many filters can exacerbate issues, creating too much water for the creatures or your tank to cope with.
In general, though, it is far more common to have an under filtered tank than an over filtered tank. This is especially true of tanks that are heavily populated, especially if you have large, predatory fish.
Bigger tanks may be susceptible to this, especially if your current filter system is not working adequately or if it is too small to cope with the load of the tank. In this case, it may be a good idea to add on a second filter, or even just a larger filter as a means of camping with the upkeep needed.
In terms of over filtering, if you unnecessarily use an extra filter, then you do not need to worry about consequences. Typically, the only result will be a cleaner, clever tank that will need to be cleaned less frequently. Of course, it is not a way to get out of cleaning, but it can help keep your water conditions better for longer.
Perhaps, on a smaller tank, it is more important to ensure that too many filters are not used as it could have an adverse effect on the tank due to more water being generated.
So bear this in mind if you are a small tank owner. You may also want to keep in mind that there is a possibility that if you use two water filters when they are not needed, you can run the risk of neither of them working as efficiently as they could.
With all this in mind, over filtering is not really an issue, and any cons of having more than one filter in your tank are far outweighed by the positive benefits.
