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Week 19: Saltwater Filtration Overview

Now that your saltwater aquarium is up and has gone through its nitrogen cycle, its time to start setting up your filtration. There are many ways, and thus many tools, to filter out your aquarium. When we say filter, what we really mean is just cleaning the water of your aquarium to make it safe and non-toxic for your inhabitants. Filtering your water also helps your aquarium look better, avoid nuisance algae, and be less smelly. There are essentially three types of filtration, and hobbyists will combine these three in different ways to accomplish their saltwater filtration. Here we do a quick overview of these and the gear you may be using. 

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Table of Contents

This Week's Video:

What is Saltwater Aquarium Filtration?

Aquarium filtration can be a vary in depth topic, depending on how much science you want to learn! Some people also like to get fancy and really advanced with a lot of gear and specialized procedures. You can certainly take this path if you wish, but a majority of hobbyists prefer to make filtration as efficient and simple as they can. This is good not only for your wallet, but also for you time commitments. Easier to clean and faster to fix if theres an issue, as well as cheaper to replace! Just don’t go too far with the “simplicity” approach when it comes to filtration, you still need a proper setup!

To help you figure out your proper setup, understand the three types of filtration that exist. You probably know by now that there is biological, mechanical, and chemical filtration.

Biological filtration is generally the most important, as it deals with the most abundant “toxin” (fish waste) and also takes some time to cultivate. Thats really the whole point of the nitrogen cycle- to establish your biological filtration. Simply put, live bacteria “eat” the waste toxins and convert them into less toxic compounds that can be filtered out in other ways or just taken out with regular water changes. Biological filtration is essentially chemical filtration, except the bacteria are your hard workers! To optimize it, you want to have a lot of surface area in the form of aquarium sand, rocks, and specially made biological media. But, you also want to have good water flow through it, as the bacteria live on surfaces, not really “in” the water. It is relatively simple if you look at it this way! 

Mechanical filtration is even more simple, as its all about removing floating food, poop, or anything else floating in your water. The smaller the “holes” of your filter pad/sponge, the more they will catch, but the more often you will need to clean them. Having extensive mechanical filtration that you clean out often is a great way to keep your aquarium clean, but also time consuming, so its a personal preference here! 

Finally there is chemical filtration. There are some compounds that bacteria and a filter pad just can’t deal with. Of course, water changes help take these out, but chemical filtration can often help fully remove these various chemicals and toxins. Simple carbon will help a ton, as well as remove smell and polish your water of any color (sometimes water turns slightly yellow over time). Consider, making chemical filtration a part of your setup! 

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Filtration Gear and Methods

  • HOB- Hang On Back filter, a simple filter that hangs off the side of your aquarium, and mainly works as mechanical filtration. Usually has enough room for some chemical or biological media, but I personally would say that these are only “adequate” for aquariums up to about 10-15 gallons. Also, they impossible to hide and make it hard to achieve a clean aesthetic. 
  • AIO- All In One filter, a misnomer as its basically a separated compartment inside of your aquarium that is dedicated to filtration. It does mean that all your filtration can stay inside “one” place, AKA the aquarium. This is a great option for its simplicity and aesthetics. Good for aquariums up to around 30 gallons, but beyond that I would recommend a sump over an AIO. 
  • Sump- basically a second aquarium underneath your display aquarium, but this one is dedicated to holding all your filtration and other gear you might want to “hide”. This is generally the best filtration “gear” as it adds a ton of versatility and space for filtration, but is also more complex and expensive. 
  • Canister Filter- This is like a mix between an HOB and sump. These are relatively rare in saltwater aquariums as they can cost as much as a sump, but are more of a hassle to work with and offer much less versatility and filtration potential. A potentially good option in specific situations! 
There are also accessories, but depending on the way you set it up, it can also be a primary filtration method. These include reactors, scrubbers, refugiums, and sterilizers.

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