Differences between a Saltwater and Freshwater Filter: Things You Need to Know

Saltwater and freshwater aquariums house completely different types of fish in them, which would lead people to believe that their filtration systems would need to be different. While it does need to be different in a few ways, the overall requirement of a canister filter or HOB (hang on back) filter would be necessary. So, let’s dive into what the differences are between a saltwater and freshwater filter!

Differences between a Saltwater and Freshwater Filter

When you ask this question, it can be easy for people to hand you the small answer of “yes”, but there is a lot more information to find out about this topic. For example, the filters you buy for both saltwater and freshwater aquariums are the same. Both canister filters and HOB filters are great choices when it comes to building up your saltwater and freshwater aquariums. However, there are other factors that need to be considered for each of these filters when it comes to the different types of water.

Saltwater Filtration

When it comes to saltwater aquariums, you will need to pay a lot more attention to the filtration processes happening. We are mainly mentioning canister filter and HOB filters, but there are so many other choices out there as well. If you’re really looking to make a long lasting move on your saltwater aquarium, a sump filter would be the best choice. However, for hobbyists a canister filter or HOB filter is the go-to choice, and for good reason!

Rate of Water Flow

When you are preparing for a saltwater aquarium, you will need to keep in mind the necessity of water flow. They require the water to be moving a lot more than your average freshwater aquarium. Not to worry though, as we have mentioned that both canister filters and HOB filters are both more than capable of running these aquariums.

How do you ensure this? Well, the easiest way to maintain this is by purchasing a filter that has the flow rate to manage it. The best way to do so is by acquiring a filter that has around 4 times the flow rate of the size of your tank. This will ensure that the filter will not be overworked, and will provide not just sufficient filtration; but that it will provide an optimized sequence of processes in your aquarium.

Tank Size

When it comes to saltwater aquariums, you will be bound to have a bigger sized tank on average. This is to help provide the fish and plantlife in your tank, a necessary amount of space to thrive in. Not to mention, a saltwater tank will not just need substrate, but you will end up requiring live rocks and live sand in there, in order to help filtration; specifically biological filtration.

These additional live substances will provide more surface area for the production and reproduction of beneficial bacteria which keeps the underwater life safe.

Freshwater Filtration

Unlike saltwater filtration, freshwater filtration is much simpler. If you end up having a decent sized tank, the most you will worry about is your filter being able to provide mechanical, chemical and biological filtration. If you get one of the better canister filters out there on the market, you will have no problem with this. The same goes for HOB filters as well!

Rate of Flow

You have already gotten a good idea of the rate of flow for a saltwater aquarium, and it runs pretty similarly in a freshwater aquarium as well. What do you need? A filter that can provide approximately four times the flow rate that is required. This will optimize the functionality of your aquarium, and ensure a healthy life for all the beings inside.

Tank Size

While it is always good to get a big tank to provide the most space for your fish and underwater plants, it doesn’t necessarily create many benefits. Thus, it is always recommended that you get a tank that is slightly larger than what you require. This is mainly because of the filtration needs, and also because it is unnecessary to get a large tank if you do not require one.

A canister filter or HOB filter with a decent flow rate and the necessary filtration means can help sustain your tank.


Q. Is there a difference between saltwater and freshwater filters?

As far as filtration goes, saltwater would require more filtration than freshwater. However, the filters themselves are not really different. You would use the same type of filters (canister, HOB, sump, etc.) for both saltwater and freshwater aquariums.

Q. Is a saltwater aquarium harder than a freshwater aquarium?

Generally, saltwater aquariums are much harder to set up and get running when compared to freshwater aquariums. However, it is easy to notice that in the long run, saltwater aquariums require less maintenance and work than a freshwater aquarium.

Q. Can a saltwater aquarium be used for freshwater?

Yes, it can! Once you have cleaned out your saltwater aquarium, you can repurpose it to maintain all the things for a freshwater aquarium.

The Takeaway

Hopefully, you have successfully managed to find all the information you were looking for when it comes to the differences between saltwater and freshwater filters. While saltwater aquariums may seem daunting at first, they are quite easy to maintain once you are into them. However, we do recommend getting some experience at fishkeeping by starting with freshwater aquariums first. Have a great day, and happy fishkeeping!

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