CHOOSE AN AQUARIUM FILTER

Choosing an Aquarium Filter

Choosing an aquarium filter is an important decision. 

A filter is essential to keep the water in your tank clean and the fish in your aquarium alive.  It can be extremely hard to sort out what is the best filter for your aquarium. 

If you start by checking out the information provided by retailers and manufacturers of filters, they all will tell you that they provide the panacea of filtration systems that will not only keep your tank water in perfect condition for your fish but will never need to be cleaned or the filter changed.  They can go on and on about the spectacular benefits of their filtration system, but who knows what is hype and what is real. 

So how do you sort if out?  Let me try to explain in straight forward  information so that you can then decide what filter(s) will work best for your tank.

Choose a filter(s), that is rated for a larger tank than you are setting up, ideally double or more (ie. a 100 l./22 gal. tank should have a filter rated for 200 l./44 gal.) This way there is plenty of filter media and maintenance will be easier with the filter remaining cleaner for longer, thus retaining maximum nitrifying efficiency.

Keeping on Top of Things - understanding filters & how they function

Keep in mind that you are working with a “closed” system.  It doesn’t’ take much to upset the balance of your tank and cause problems for your fish.  The trick to keeping things running smoothly is to monitor your tank daily, making small adjustments rather than letting things get too far out of balance to fix.  One of the best assistance to this is to have filter(s) that are right for your tank. And believe it or not, it doesn’t have to be the most expensive filter in the store to provide you the filtration you need.

There are basically three things that can cause the balance to change in your tank:

• The pollution and chemicals in the water from your tap, or believe it or not, even pollution out of the air.  
• Gunk that ends up in the tank from dirt and dust;
• Excess food waste (the fish don’t always eat everything you give them,) and possible toxins from that waste.

To keep your tank in a state that your fish can flourish you need a system of filtration, and that filtration occurs in three ways:

1. Biological - provides micro-organisms to maintain water quality.

This is probably the most important type of filtration for your tank.  All bodies of water have a “nitrogen cycle,” 

Nitrite buildup is easily removed from your tank by regular partial exchanges of water and if you have them live plants can help to convert it to harmless nitrogen gas. 

But, it is ammonia that is the most deadly and in fact the most common cause of the death of tropical fish, particularly for “new” Aquarists.  In the beginning people have a tendency to “fuss” with their tanks a little too much.  I realize I have told you, you need to monitor your tank, but the trick here is balance. 

You do not want to introduce you fish into your tank before the nitrogen cycle has been established, and even after this, if you introduce new fish into the tank the cycle can be disrupted because of the increase in waste.  Or, you can deplete the friendly bacteria by the use or over-use of antibiotics or changing the water too much.

I realize this is all a little overwhelming, but hang in with me and all will become clear!

Healthy Environment

What you are working towards is a healthy, stable environment for your fish.  This means you need to have enough friendly bacteria to convert the amount of waste being produced in your tank.  There are products available to establish bacteria faster and to remove the ammonia in an emergency, but the best way is to provide this stable condition is by having:

• Enough oxygen

• The right surface materials

• The right amount of surface materials

Surface Materials

In order to have enough bacteria in your tank you need to provide a surface that will let the bacteria grow, that is a surface with enough rough areas or “nooks and crannies” (like they say on a well know English muffin commercial) for the bacteria to be able to colonize.  One place for this is the gravel on the bottom of your tank; the second is within the filter and filter medium that is used in it.  This is important because you will need to choose a filter with the right amount of medium for the “load” it will have to process.

Then of course there is oxygen.  Not only do your fish need the proper amount of oxygen in the water, but the bacteria will also be using that oxygen.  In fact if there is an increase of waste for some reason in your tank, the bacteria can deplete the oxygen and endanger your fish.

Ok, so let's talk a little about the bacteria – what you need in your tank isn’t any old bacteria but aerobic, or like I said earlier, they need oxygen to exist.  So the way to do this is to make sure you have enough “aeration” going into your tank.  This only becomes important because the very filters you are using with the right amount of surface to allow your bacteria to survive, can make it difficult for the right amount of oxygen to pass through it and this then allows nitrites to build up. 

So with all that what it really means for you is that for the health of your aquarium, you need to have enough surface area or biological filtration to handle the load you will be placing on it. 

2.   Mechanical – physically removes particles from the water

This is where a “filter” comes into play.  Most filters that you can purchase work well for this purpose.  It physically removes the particles that can clog the filtering medium and get in the way of the biological bacterial process.  Not much explanation is needed here, until we begin to look at the different mechanical filters and what your needs may be.

3.  Chemical - removes ammonia or adds oxygen to change the water quality.

The way most chemicals get into your tank to cause problems is through medications.  This can be avoided by using a quarantine tank, rather than treating your main tank, but if not you need to be aware of the need for a chemical filter to remove the medication after treatment is concluded. 

Other chemicals you need to be aware of come from fish food, or phosphate and silicate from tap water or other additives.  Phosphate and silicate cause a condition called “algae bloom” and this can be treated by using chemical filtration (if they are coming only from your tap water then a “reverse-osmosis” purifiers or water deionizers may be the solution.)

Filter Types

Now lets talk about the different types of aquarium filters so that when you walk in to the fish store with your shopping list you will already know what you are looking for.  This chart is a quick look into the information you need, click on the Filter Type  to find more detailed information.

S - Saltwater     F - Freshwater      gal - gallon(s)      Bio - Biological 
Mech - Mechanical         Chem - Chemical

Box or Corner Filters (Internal)

This is a plastic box that relies on air pumps to push water through the media in the canister.  The flow rate of oxygen through this filter is low, so they won’t work with a heavily stock tank.  They need to be cleaned often but are simple to clean.  This inexpensive filter works as mechanical and chemical filters to back up smaller but you may find they are still inadequate biological filters.

Canister Filters

This filter is designed for larger aquariums (30 gal. and above).   One of the benefits is they can be placed under or beside the aquarium out of sight.  They also aren’t as limited in size because they aren’t submerged in the tank or hung on the outside.  They usually have all three filtration methods and come with a variety of design features.  The one problem may be the problem of keeping enough oxygen going into the tank when there are surges in power or power outages.  Keep in mind that the more biological media the better when choosing this type of filter.

Diatom Filters

These mechanical filters are specialized in using a media called “diatomaceous earth,”  this is a sediment made from the skeletons of single-celled microbial algae or diatoms, who use their unusual pore structure to trap tiny particles.  This type of filter is the best mechanical filter available.   The promote faster healing and can improve water conditions, in fact they can provide the crystal clear water conditions.  Unfortunately, a drawback of these filters is they clog easily, so they shouldn’t be used continuously.  They should be used in combination with another primary filter system so that they are used for short periods to maintain and improve water conditions.

External Power Filters

Are filters that hang on the back or side of the tank.  This is why they are sometimes called “hang-on” filters or HOB power filters.  They are extremely popular with beginning aquarist and come with aquarium kits that can be purchased with everything included.  The tanks they are used with are usually smaller (under 50 gal.) they can be used for either fresh or salt water tanks.  These filters usually include chambers for both mechanical and chemical media although some come with a Bio Wheel filter or a “Millennium” filter, that has a mechanism for biological filtrations.  A common problem with this filter is that the media chambers are too small to provide enough surface area for the bacterial bed, particularly if your tank is stock heavily.

Fluidized Bed Filters

This filter houses a biological filter that doesn’t get disturbed.  The way they work is that a fine grained sand is suspended in a column of water.  The sand is a great surface for biological buildup for filtering, but the sand is easily disturbed by the water flow and this disrupts the bacterial buildup used in the filter. 

These filters are best used in planted aquariums where depleted CO2 is not a concern because in a power outage, they can often remove the oxygen from the system and causing a quick build up of nitrates.

Some fluidized beds are reactors for chemical media and work the same way with sand suspended in a column of water.  The sand allows for a highly efficient chemical filtration, but it is still not as effective.   If the fluidized bed devices are referred to as a filter and not a reactor then it is probably a biological type

Internal Power Filter

Meant to be submerged inside the aquarium they are very similar to to the external power filter.  A specialized salt water filter is needed if you plan on using this type of filter in your salt water tank.  These filters tend to be smaller than the external sister, which also means they have smaller chambers for media.  This filters are frequently used in turtle or low water habitats.  They can be used as a supplement to canister filters in large tanks but because they can be seen inside the tank they aren’t the ideal filter.

Sponge Filters

This filter consists of a piece of sponge or foam with an intake tube for an air pump to push water through them,  They are the simplest filters on the market.  They can offer good mechanical filtration and are sometimes used as pre-filters in powered filters  The proved excellent biological filtration with area to colonize bacteria.  If you have a small tank, you may not need any other filter, and if you are raisin fry fish (baby fish) this is a perfect filter as the tiny fish can’t get sucked into the filter.  They also work well in quarantine tanks where a chemical filter would be a problem.  The only care they need is to be gently rinsed under water, but this also can upset the biological functions.  If you have a larger tank, they work as a biological supplement but not a s primary filter.

Undergravel Filters

This filter consists of a filter plate that sits under the aquarium gravel and has “uplift” tubes that move water slowly through the through the gravel and the plate. They are powered either by air pumps or air stones. These filters were used more in the past than they are now because they are inexpensive and easy to use.  If you already have a tank set up they are not a good choice as you have to completely break down your tank disrupting the tank conditions..  They do have good mechanical filtration and treat biological filtration and there are chemical cartridges that can be added to these filters.  If you have live plants in your tank, they tend to do poorly with type of filter.  You will need to vacuum regularly and you need to monitor the buildup the tend to develop underneath, they also tend to loose efficiency over time.  There or varied opinions about this filter, so you may want to do some more research before deciding whether to use this filter or not.

These filter can be the complete filtration system in your aquarium and if you have a heavily stocked tank there is no better biological filters. Particularly salt water tanks with reefs etc.  but they can be difficult to maintain so they aren’t the best for a newbie aquarist.  This filter works by water dripping or trickling slowly through the mechanical media gathering oxygen as it moves through the biological filter.  They also have greater surface area making them the best biological filters available. If you have a large tank with a sump (a external tank for water to be pumped into your aquarium) they are popular and are used in large saltwater/reef aquariums.  They are complicated to maintain but they can’t be beat for large heavily stocked tanks.

Keeping Your Tank Healthy

The higher the “flow rate” of the filter,  the better for your primary filter, particularly if you are setting up a larger tank (over 50 gallons)  Power filters have higher flow rates

For smaller fresh water or saltwater lightly stocked tanks an external power filter may be enough, particularly if it has a bio-wheel, or a wet/dry compartment.  You can always add an inexpensive sponge, canister or internal filter if you find your primary filter isn’t quite enough.

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The bottom line is this = the greater surface area for filtration, the better biological filtration you will get, which is the best for optimal conditions.  Don’t stress if you are not getting the filtration you need, you can always add another filter to supplement.  Keep on top of the ammonia, nitrate and nitrite levels in your tank so you can make small adjustments which are much easier than waiting until things are irretrievable.  A sponge filter is a great, inexpensive way to supplement, they are also easy to clean, unbreakable and easily replaced. 


 

Adding a diatom filter (If your budget allows) to your primary setup is a great way to assure you will have crystal clean water and it is a great back up to your main filter in keeping everybody healthy. 

Tips For Keeping Your Fish Healthy and Happy

• Although the larger the tank the easier it is to correct water conditions with less consequence,  the larger the tank the more water circulation you will need to cope with, so you are better off starting small and after mastering that moving to a larger tank.

• As I said before, get a larger filter system than is recommended for your tank, the filtration will work at its best that way (don’t do that with undergravel filters which are built to fit to the bottom of a tank exactly.)

• Regular filter cleaning MUST be part of your cleaning routine (there are great tools available to make it easier)

• Regular partial water changes is essential along with gravel vacuuming, It is part of the joy of being an Aquarist

• Regularly monitor water conditions, ammonia and pH to avoid problems.

• Partially changing the media in a one compartment filter for biological media can be made easier by using filter bags.

• Always clean the filter media according to the directions – yes you have to read the directions – you make the filter useless if you don’t manage the filter media correctly.  DON’T change all the filter media at once, you need to preserve the bacterial bed In your tank.

• It is important to keep water and oxygen flowing through your filter (particularly in large tanks.) You need to assure you have proper circulation – aeration and trace element distribution.

• A protein skimmer can really make a difference on the stress to the filters in a salt water tank. 

Don’t skimp on purchasing off-brand filters and equipment, stick with recognized industry manufactures to assure that you get the important quality.  Check out the reviews of equipment you are interested in purchasing and  take advantage of the technology and design improvements.  It will save you in the long run in knowing your fish and aquarium are in quality products and equipment.

So you are now ready to choose the filters you will need for your aquarium.

I am sure in the research you have done in the learning process for your aquarium; you will have come to realize there is controversy about how to properly set up your aquarium, the right type and configuration of filters etc, etc.  The only way to really sort this out is to jump in and begin working with all the equipment that is necessary to keep an aquarium at its best.  Through trial and error, you will come to your own conclusions about all of this so don’t worry about it. Use your own judgment after learning the basics about what is needed to maintain your tank.  The information here and the other information here at Tame That Wild Thing! should help you get off on the right foot.

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