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How to Setup a Freshwater Fish Tank: Part 2

February 4, 2020
How to Setup a Freshwater Fish Tank: Part 2

Welcome to Part 2 where we dive deeper into filtration and water quality! You’ve gotta get this right as there’s nothing worse than bringing a fish home from the store, only to see it die because your water quality isn’t right.

There are three types of filtration: Chemical, Mechanical and Biological Filtration

Let’s first talk about the actual make and model of the filter I’m using. And if you didn’t read Part 1, it’s there we go into the basics of tank, heater, etc.

Filter Model Brand & Type

As mentioned, I’m using an over-the-back filter from Marineland. In 2020 Marineland came out with a new Penguin Pro line that features killer improvements which IMHO will rival the ideal of canister filtration for some people.

In the video below I talk about the improvements in the new filters as compared to the older Marineland Penguin models.

Now let’s discuss the three methods of filtration that you need to be aware of for your fish tank!

Mechanical Filtration

This type of filtration is simply sponges, filter pad and other methods that remove large particles from the water. The default filters that come with Marineland penguin products contain a filter pad, which is chemical filtration. You can also add a sponge to the bottom as mentioned in the video.

Chemical Filtration

Activated carbon is also contained in the default filter cartridges. What is activated carbon? It’s material with tiny pores that can remove things like chlorine, tannins and phenols from tank water.

Question: Can activated carbon remove enough chlorine from tap water to keep fish safe? No. If you dump tap water into your tank, you’ll kill your fish. Also, carbon exhausts quickly, so you have to change it frequently or it’s not doing anything for you.

Important Tip: Chemical filtration does not remove nitrite, nitrate or ammonia. These must be handled with water changes and biological filtration.

Biological Filtration

This method is the most important for the health of your tank. I didn’t understand this at first. I thought tank filtration was all about chemical and mechanical filtration. You know, removing things from the water. These are important, but without biological filtration your fish will die, because as mentioned, chemical filtration cannot remove ammonia, nitrites or nitrates from the water.

So where does ammonia, nitrites and the like come from?

To understand this, you need to wrap your head around the nitrogen cycle that happens in a fish tank, which is how God designed it in nature. Aquarium people will call it “cycling a tank.” And it has to do with beneficial bacteria.

Here’s what happens in a nutshell:

1) Things like fish food and fish waste decay in your tank and create ammonia.

2) Nitrifying Bacteria turns the ammonia into nitrites.

3) Nitrifying Bacteria then turns the nitrites into nitrates.

4) Denitrifying Bacteria consumes nitrates.

Without biological filtration, fish food and fish poop alone are going to produce toxins that will wipe out all of your fish.

How to Remove Ammonia & Nitrites

As you now understand, biological filtration is done by living bacteria in your aquarium. And nitrifying bacteria handles ammonia and nitrites. This bacteria requires oxygen to live, and is cultivated with biomedia.

How to Remove Nitrates

At the end of the nitrogen cycle you end up with the nitrates. Nitrates are less toxic for fish than ammonia and nitrites, but they’re still no good. Plus, you’ll deal with a lot more algae issues with higher nitrate levels, and any shrimp and the like will suffer before your fish do.

There are three ways to remove nitrates from your tank water.

Denitrifying Bacteria. This bacteria grows in areas that don’t have oxygen, and it consumes nitrates. For example, in the new Penguin Pro filters you can add media in two places that will encourage the growth of denitrifying bacteria. It is more difficult to grow this bacteria than nitrifying bacteria.

Live Plants. A planted aquarium is SO MUCH BETTER than filling your tank with plastic plants shipped in from China. Living plants not only look beautiful, but they help your eco-system by providing oxygen and consuming things like waste and nitrates!

Water Changes. You should be removing some of the water on a weekly basis. If you have a heavy planted tank, you can go longer. I remove about 8-10% of the water every one to two weeks on my planted tank.

Oh man! That was a lot of detail you never knew you needed to know about a fish tank, right? Don’t worry, once you have stuff in place this is pretty easy to maintain. Way easier than other pets like dogs, cats, birds, etc.

Real World Example

So now let’s take a look at this in reality. I’m going to show you what I do for each of these areas with my 29-gallon tank and Penguin Pro filter.

1) Chemical & Mechanical Filtration

I use the Marineland reusable filter cartridges (size C for the Pro 275). These allow me to add in my filter pad (mechanical) and then any type of carbon (chemical). The combo aids in removing chlorine, tannins and large particles, etc. I only add chlorine filtered water to my tank on water changes, but I have a piece of wood in the tank that releases a lot of tannins. The Marineland Zeolite carbon mix helps with that.

Marineland reusable filter cartridges with the Marineland Zeolite rocks.

2) Biological Filtration

The Penguin Pro has three places to add biomedia for fostering the growth of beneficial bacteria. The first is their exclusive Bio-Wheel that rotates with the water as it enters your tank. And remember, even if your Bio-Wheel looks dirty, never replace it. Ever.

The exclusive Marineland Bio-wheel.

Next on the Penguin Pro are the reusable filter cartridges. For the first cartridge (they hold two) I use filter padding and carbon. But for the second filter I fill it with biomedia. I’m using Matrix from Seachem (shown below).

A Marineland filter cartridge filled with biofiltration media from Seachem.

The third area on the Penguin Pro filters is a basket inside the filter that can hold more biomedia. I also fill this will Seachem biofiltration media. Seachem Matrix™ is a high porosity biomedia that encourages the growth of both nitrifying and denitrifying bacteria, and it basically lasts forever.

The new basket on the Penguin Pro models that holds biofiltration media!

Live Plants

My next attack on nitrates (besides water changes) is a semi-planted tank. I currently have 10-11 live plants in my 29-gallon setup. These not only provide oxygen, but help absorb all of the bad.

My 29-gallon planted tank with eleven live plants.

For plants to live, they need a good substrate (don’t get painted aquarium rocks). They also need a planted tank light (I use the Finnex Planted tank light), and supplements like Seachem Flourish and Seachem Flourish Iron (for red plants). The most expensive part is the light. Plants and plant food are pretty cheap.

Water Changes

As you now know, water changes are part of a healthy fish tank — Something I didn’t do as a kid, much to the demise of my fish. But if you have a planted tank, you’ll have to do water changes a little less since the plants absorb harmful things in the water that an all plastic tank cannot.

Water changes are key and should be done monthly! It’s easier than it looks.

I use a simple gravity-fed vacuum for my water changes. It allows me to vacuum up a lot of waste from the substrate while doing a water change. How much water should you change? That depends on how many plants and fish you have. I only take out probably 4-5 gallons max when I do a water change on my 29 gallon tank, but my tank only has 3 fish, a snail and a shrimp.

Keep tabs on water quality with a product like the one pictured below from Tetra.

Here is a water test kit from Tetra that measures ammonia, nitrate, nitrite, chlorine, etc.
Tip: If you run into low PH levels, you can up this with a little baking soda. I added a teaspoon to my 29-gallon tank and then PH was golden (after 24 hours or so). Don’t add too much as it also raises alkaline, and rapid spikes can kill your fish.

Congrats! You now understand how to maintain a healthy tank. Next let’s move on to populating it with fish! This will be covered in Part 3.

Written By
Kyler Boudreau

Kyler experiences life with his wife Sandi and his daughter Journey. He is an independent filmmaker ( and designed a CRM for network marketers (

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