The Basics of Filtration

by Steven P Parker

There are many types of filters on the market and many different ways to go about accomplishing the task of filtering your water. All filters use at least one of three types of filtration, while many employ all three types together.

Mechanical:
Mechanical filtration is accomplished by using a material to trap waste products that are floating in the water column. A sponge, or floss, or pad may be used to trap the particulate matter and then each time you service the filter this material is cleaned or thrown away. This media may be rinsed in tap-water.

Chemical:
Chemical filtration is accomplished by using carbon, Purigen, or some other resin to interact with toxins in the water column by chemically bonding to them, trapping those toxins within the product. I generally do not use any form of chemical filtration in my tanks! There are times when it is needed, such as for medication removal, otherwise its cost doesn't justify its use regularly.

Biological:
Biological filtration is the most important part of maintaining excellent water quality. Various small bacteria in you filter eat toxins produced by fish waste and convert it into less and less toxic substances. Basically your fish release ammonia, which is extremely toxic to your fish. Ammonia is converted by bacteria into nitrite. Nitrite is also very toxic to your fish. The nitrite is then converted by another bacteria into nitrate. Nitrate is also toxic to your fish at high levels, but there are no other good bacteria to efficiently break the waste down further so it must be physically removed by partially changing the water regularly.  These beneficial bacteria colonize the biological media and live on its surfaces.  This Media should never be rinsed in tap-water, and should only be rinsed in used tank water!

 

 

Because Cichlids are very messy and dirty fish they need more than the usual amount of filtration. As a general rule of thumb Cichlids require twice as much filtering capacity as a normal community aquarium. So if a certain filter is rated for an aquariums up to 60 gallons you would either need two of these filters to handle a 60g tank, or one of these filters on a 30g tank. Generally it is advisable to use two filters instead of a single over sized filter. The purpose for this is that each filter acts as redundancy for the other as well as allowing for alternating servicing schedules so you disturb the biological colonies in each filter less often.

For Cichlids, my personal choice is a combination of a canister filter and a HOB style, each rated to handle the tank alone. This combination provides top-notch mechanical with excellent biological filtration providing redundancy should one fail, while allowing longer servicing schedules for each. In my opinion this is the best overall and most cost efficient method to use long term for tanks under 6 feet in length. A 6-foot tank is best served with a wet/dry filter as the costs of multiple canisters and HOBs are much less practical. My recommendation is a properly sized Aquaclear HOB and a properly sized Fluval in combination. There are plenty of other good choices for both the HOB and the Canister, with Emperor, Rena & Ehiem coming to mind. I have always preferred the Hagen products because they have a long standing reputation in the fish hobby and replacement parts are readily available. (Recently Hagen, the parent company of Fluval and Aquaclear, has raised its prices substantially so that there is no longer a clear cut choice, and my pocket book is now backing the Emperor/Rena combo.) The Design you find the easiest to maintain will be the best choice for you. Ultimately make sure you like how the routine maintenance must be performed when judging your purchase. Some filters require you to purchase media constantly throughout their lifetime, but simplify the maintenance routine by making it a snap like the Emperor, and others provide you with all the media you will need for a majority of its lifespan like the Aquaclear, but require a longer cleaning practice. Some people prefer the convenience of disposable media and others like the renewable media, either way is good provided you perform the regular maintenance schedule with precision.
(Following a schedule closely is the hardest part for many people, I too am guilty of procrastination. Learn Discipline!)

Maintenance
Every filter has a different maintenance schedule. I can give you some guidelines, but each tank is unique so you will have to "get a feel" for what works best for you. For all filtration types except the Sump-wet/dry or the Canister filter, a good starting point is every month rinse out the media in a bucket of tank water (So you don't kill the bio-filter) and return everything back to operation ensuring good water flow. Often with HOB style filters they will have water backing up over the wall near the intake tube. This is a sign of clogged media and will happen less on immature tanks, and more frequently on mature tanks. For Canister filters you can probably go from 3-4 months between cleanings depending on both your bioload and which brand of filter you have and what supplemental filtration is provided. A good tip is to write your next filter service on a piece of tape (Like an oil change) as a reminder. If you have two filters alternate them and service one filter every two weeks, which will disturb your biofilter even less.

Bedroom filtration Setup
WARNING: This is not a preferred setup for Cichlids. If you are very sensitive to noise and the sound of water flow, then I recommend a combination of a Whisper HOB and an Eheim Canister. These two can combine for an extremely quiet and effective system at both higher cost and some loss of redundancy. Its a good idea to upgrade the Whisper HOB with replacement bio-cartridges. These are vastly superior to the regular Whisper cartridges providing much more surface area for bacteria to colonize. The only problems that may arise is aeration may not be adequate for overcrowded stocking levels due to the surface being disturbed less. This is one sacrifice we make to have a quieter environment.

For more info on filtration click here.