Despite the low fish population, efficient filtration in the planted aquarium is an absolute must. As with regular freshwater fish tanks, I strongly recommend the use of canister filters (packed with biological filtration media) in planted aquariums.

In this Aquarium Filtration article, therefore, I’ll discuss the proper use of canister filters in the planted aquarium.

Defeating Algae: Make Planted Aquarium Care Easy

The use of efficient filtration methods in the planted fish tank is vital to for the well-being of your plants!

In a regular freshwater aquarium, algae growth is not a big problem because you can easily wipe the clingy green buildup off of tank walls and aquarium decorations.

Algae growth on plant leaves, however, not only looks unattractive, but it also may cause irreparable damage to your live aquarium plants. Algae will obstruct the penetration of life-sustaining light into the plant leaves, and it’ll significantly limit gas and nutrient exchange between the plants and the surrounding water. Unfortunately, wiping and/or scraping algae off of leaves is not good solution, for doing so will damage the plants.

For the above reasons it is critical that you maintain optimum water conditions. You can do so by using clean RO water, keeping from overstocking your tank with fish, and not overfeeding the fish you have. In addition to keeping the water clean, you should also consider the benefits of promoting strong water circulation. Doing so will prevent many problem algae species from growing on your plant leaves.

Water Flow in the Planted Aquarium

Unlike tropical fish, aquarium plants cannot move about the fish tank to find nutrition. Live plants can only utilize the fertilizers and CO2 (for those of you who use CO2 reactors) when these substances make physical contact with the plant leaves (common sense, right?).

That’s why sufficient water flow is essential for success with live aquarium plants. At the same time, you don’t want to create excessively turbulent tank conditions. Strong currents will rip aquarium plants right out of the substrate!

So, what is the right amount of water flow?

Well, if you’re like most freshwater aquarists, you probably rely on your filter to provide most, if not all, of the water movement in your fish tank. Since the filter’s water pump is the mechanism that actually moves the water, you can choose the right filter for your planted aquarium by taking a look at the flow-rate of the filter pump.

World renowned aquarist, Takashi Amano, suggests the following filter pump flow-rates for planted fish tanks: “6 liters (11/2 gallons) per minute flow for 60- to 180-liter (15- to 45-gallon) aquariums, 20 liters (5 gallons) per minute for 300- to 6000liter (45- to 75-gallon) aquariums, and 30 liters (8 gallons) per minute for 300- to 600-liter (75- to 150-gallon) aquariums” (Amano 95).

Although the above flow-rates may seem high, keep in mind that the force of the water leaving the filter is quickly defused as the out-flowing water encounters resistance as it makes its way into the aquarium. To put it more simply, water movement, while strong at the base of the filter out-take, is subtle in the rest of the aquarium.

Nevertheless, the water flowing out of the filter may damage plants located directly in front of the filter out-take. In fact, Amano suggests positioning the filter out-take tube towards the front of the aquarium where shorter foreground plants grow (96). These low-growing plants are not affected by strong currents, and they don’t obstruct water movement.

As you can see, filtration in the planted aquarium takes some consideration. Still, five minutes of planning beats five years of looking at a mediocre aquarium! It’s well worth the extra bit of effort.

Bibliography:

Amano, Takashi. “Filtration in the Nature Aquarium.” Tropical Fish Hobbyist, January 2007, 94-96.

In this Aquarium Care 101 post, however, I’ll go over the most important of the three primary filtration methods: biological filtration.

Aquarium Care principle 4: Understanding Ammonia

No filtration form is more efficient than biological filtration!

Biological filtration depends on the work done by a group of beneficial bacteria. These bacteria occur naturally in almost all bodies of water, and, most importantly, they consume fish waste.

What makes fish-waste harmful anyway?

Well, the fish poop itself is not the thing that causes potential problems in the home aquarium. Instead, it is the toxic compounds released by fish poop (and by other forms of decaying organic matter) that can make Aquarium Care a nightmare.

In particular, Ammonia, a substance that is highly toxic to all tropical fish, is readily released by fish poop. This toxic substance is also released by your tropical fish through the gills.

Ammonia is made up of one nitrogen and three hydrogen atoms. That’s why scientists abbreviate it as NH₃. In other words, NH₃ describes the chemical makeup of Ammonia.

In the home aquarium, Ammonia may also be released in the form NH₄ (called Ammonium), which is not toxic to tropical fish.

Nevertheless, whether your fish release Ammonia or Ammonium depends on several factors, many of which (such as pH and temperature) are beyond the range of what most tropical fish will tolerate.

Aquarium Care Principle 5: Biological filtration makes Aquarium Care easy

Ammonia can be removed by means other than biological filtration, but that’s doing things the expensive and hard way!

Those beneficial bacteria will do a lot of the work for you if you provide them with aquarium conditions that will allow them to thrive.

But, before I get ahead of myself, let me briefly describe how the beneficial bacteria remove Ammonia from your aquarium water.

There are two groups of beneficial bacteria, and they detoxify your aquarium in a two step process.

1) The first group of beneficial bacteria absorbs Ammonia and produces Nitrite as waste. Nitrite is also toxic to tropical fish, but, fortunately, the process does not end here.

2) The next group of beneficial bacteria absorbs Nitrite and produces Nitrate as waste. Nitrate is the relatively harmless end-product of biological filtration.

And, that’s it. That’s all there is to it!

Aquarium Care Principle 6: Encourage the growth of beneficial bacteria in your aquarium

So, how can you encourage these beneficial bacteria to grow in your aquarium?

The beneficial bacteria are not free swimming. That means that they need places in your aquarium to cling to. In other words, they must have a surface area on which they can grow and multiply.

These clingy bacteria homes most often include 1) filter material and 2) the sand or gravel at the bottom of your aquarium.

1) Canister filters are great at providing biological filtration. I pack my canister filters with bio-filtration media. This media looks like a bunch of highly porous blocks which provide the beneficial bacteria a lot of surface area.

My canister filters are, essentially, massive beneficial bacteria colonies!

2) The bottom material of your aquarium constitutes the largest surface area in your aquarium! The sand or gravel in your aquarium, therefore, houses the most abundant population of beneficial bacteria.

The subject of gravel type and biological filtration is a complex one, and you can refer to Chapters 4 and 8 of the book to learn about the ins and outs of proper substrate choice and care.

Basically, though, the larger the aquarium is, the more gravel or sand it will house. More gravel or sand, in turn, translates both to a larger surface area and to more beneficial poop-eating bacteria!

This is just one more reason why large aquariums are easier to care for than are their smaller counterparts.

Let’s take a look at an aviation metaphor to flush out the concept.

Did you know that the Wright Brothers were one of many pioneers of powered flight?

They, in fact, had a lot of competition. So, why does history remember the Wright Brothers, but not their competitors? How were the Wrights able to achieve in 1903 what Samuel Pierpont Langley, Alberto-Santos Dumont, and many others couldn’t?

Very simply, the Wright Brothers designed an airplane that worked according to the natural laws.

Langley, on the other hand, tried to overpower nature by mounting brawny engines on his airplane designs. Yes; these heavy engines produced a lot of horsepower, but they also weighed his airplanes down. In fact, his aerodromes had to be launched from a catapult just to get off the ground! …And, even then they didn’t work!

Basically, the Wright Brothers were able to beat their competition because they understood how air behaves. By mounting small engines on efficient wing surfaces, they effectively applied their knowledge of physics to their Kitty Hawk design. They knew that they couldn’t overpower nature, so they decided to work with it!

Well, your filter (the actual machine) is the engine that powers your aquarium.

While many filter designs (the hang-on power filter comes to mind) try to replace biological filtration with brut strength – with mechanical and chemical means of cleaning the water, the best aquarium filters (the most notable of which is the canister filter) optimize Mother Nature’s proven filtration method.

You can learn more about the many benefits of canister filters in The Kick-Ass Aquarium. Very simply, though, canister filters are great at providing biological filtration. That’s because they contain ultra-porous blocks that provide beneficial bacteria with a lot of space to grow on. Canister filters, in effect, increase the total amount of bio-filtration that occurs in your aquarium!

So, don’t follow Mr. Langley’s bad example! Don’t try to overpower nature!

My sincere advice is to take advantage of nature’s timeless filtration method. Increase that beneficial bacteria count! The more beneficial bacteria your aquarium houses, the more stable your fish tank environment will be! Believe me, your tropical fish will reward you for the wise choices you make!

In particular, some people still use the undergravel filter (UGF), and many aquarium stores and pet shops continue to sell these obsolete filters. My sincere advice is to stay away from these ancient filter designs.

In The Kick-Ass Aquarium, I explain the drawbacks of UGFs in detail, and I point to a few great alternatives. If you read my book, you understand how UGFs work, so I won’t spend more time on the matter. Instead, I’ll talk about the flawed arguments supporting the use of undergravel filters.

One recent argument comes to mind. In his article, “In Defense of the Humble UGF,” Gio Maletti suggests that undergravel filters are well suited for growing live aquarium plants, and that they are efficient and barely visible.

Plant roots do best in fish tanks that have a sand or clay bottom (both materials look great, by the way), and they don’t tolerate a lot of water movement through the substrate, through the bottom material.

Well, the UGF can only be used with gravel because sand will clog this type of filter. Also, UGFs will produce a lot of water movement through the substrate!

Maletti’s solution to these two drawbacks seems simple. He suggests placing plants in pots that contain sand or clay in order to alleviate the two problems caused by undergravel filters (Maletti 95). So, now we need plant pots to make UGFs work? Apparently, the list of equipment needed for using undergravel filters is growing!

That brings us to the next issue: bulkiness. UGFs consist of a large plastic tray and two or more wide plastic tubes that protrude from the bottom of the fish tank. The tray will take up an inch of vertical space, thus decreasing the height of your aquarium by that amount! Also, the plastic tubes are far from inconspicuous! On top of this, you’ll need those bulky plant pots to make the whole setup work!

To Maletti’s credit, he correctly asserts that undergravel filters encourage biological filtration (95). But, there are much better ways of promoting this very important filtration method.

First, keep in mind that the beneficial bacteria that provide biological filtration naturally occur in the gravel or sand bed. In fact, sand has a much larger total surface area than gravel, so a sand bottom will house more beneficial bacteria than will a gravel bottom. The more poop-eating bacteria you have, the cleaner your water will be. Again, UGFs can only be used with gravel.

Also, you can increase water flow through the sand or gravel bottom, but to a degree that won’t harm plants, by taking a simple step that will actually make your aquarium look nicer!

By simply shaping the sand into a wavelike surface, as opposed to a completely flat surface, you will significantly increase water flow throughout the sand or gravel bed. And that’s all there is to it!

Finally, why rely on a bulky UGF to promote biological filtration when you can actually increase the beneficial bacteria population in your aquarium by attaching a canister filter to your fish tank?

With a UGF, you will only encourage the biological filtration that is already occurring in the substrate. As we discussed above, doing things this way is problematic.

By using a canister filter, on the other hand, you will increase the total amount of biological filtration! That’s because the beneficial bacteria will now have two places to colonize: the sand/gravel bed and the canister filter!

In short, UGFs are cheap (in terms of both price and quality), and any money you’d spend on them you would be wasting!

Bibliography:

Maletti, Gio. “In Defense of the Humble UGF.” Tropical Fish Hobbyist, November 2006, 94-95.