I am writing this because of the many questions I see on MFK about filtration. And because I believe aquarium filtration is highly misunderstood, and that misunderstanding is the cause of many would be aquarists leaving the hobby, and many of the fish illnesses, maladies and deaths they experience.
First off, why should you believe me?
My major field of study was Environmental science, with an emphasis in wastewater and drinking water filtration technology. I went on to work for almost 20 years as a chemist/microbiologist in a drinking water filtration plant, where part of my job, was to assess the efficiency of 48 filters through scientific analysis. These filters together averaged a flow rate of 300 million gallons per day.
I have also been an aquarist for over 50 years.
That out of the way, here are some of the misunderstandings I see, and posed as similar questions.
Are manufacturer filter stats adequate for my tank?
Most stats are based on an average community tank.
This means the equivalent of a tank with maybe 4 tiger barbs and a pair of 3”-4” gouramis, or a tank of 6 guppies and a betta, or a tank of 6 small tetras and a pair of angelfish, and maybe some kind of small catfish or loach in each tank.
One 10” oscar (or any other similar sized cichlid) is nearly the equivalent of all of these fish combined. So to me this means most tank manufacturer rated filters are undersized by at least 3 times for 1 oscar.
But this begs another question…does a filter actually remove all the bad things in a tank?
To me the answer is no.
When the biological media in a filter is sized properly for the fish the tank, it will serve to remove toxic ammonia and nitrite, and help to covert those toxic substances to, or store “less toxic” nitrate.
The mechanical media in a filter only “stores” particulate.
Does it remove it from the system? No.
It stores mulm, fish feces, and other junk, and is a place where those substances further metabolize and can leach invisible, chemical substances back into the water.
Unless the aquarist purges the media of this stuff, it is still in the system, and still in the tank, unless removed by water changes, or some other chemical reactor, or substance.
In my filtration plant work, biological filters needed to be backwashed every 5 days, otherwise non-beneficial bacteria would proliferate, and particles would break through, which lead to a lessening of filter efficiency.
I believe some kind of similar routine needs to be done on aquarium filters.
This leads to another question…
My water is perfectly clear, doesn’t that mean it safe?
No.
Most of the substances that are toxic in either an acute way, or chronic way to our fish, are invisible.
And just because an aquarium is cloudy, doesn’t mean its unsafe.
Anyone that lives next to the Mississippi river knows, the water can be mud brown and still be teaming with fish.
First off, why should you believe me?
My major field of study was Environmental science, with an emphasis in wastewater and drinking water filtration technology. I went on to work for almost 20 years as a chemist/microbiologist in a drinking water filtration plant, where part of my job, was to assess the efficiency of 48 filters through scientific analysis. These filters together averaged a flow rate of 300 million gallons per day.
I have also been an aquarist for over 50 years.
That out of the way, here are some of the misunderstandings I see, and posed as similar questions.
Are manufacturer filter stats adequate for my tank?
Most stats are based on an average community tank.
This means the equivalent of a tank with maybe 4 tiger barbs and a pair of 3”-4” gouramis, or a tank of 6 guppies and a betta, or a tank of 6 small tetras and a pair of angelfish, and maybe some kind of small catfish or loach in each tank.
One 10” oscar (or any other similar sized cichlid) is nearly the equivalent of all of these fish combined. So to me this means most tank manufacturer rated filters are undersized by at least 3 times for 1 oscar.
But this begs another question…does a filter actually remove all the bad things in a tank?
To me the answer is no.
When the biological media in a filter is sized properly for the fish the tank, it will serve to remove toxic ammonia and nitrite, and help to covert those toxic substances to, or store “less toxic” nitrate.
The mechanical media in a filter only “stores” particulate.
Does it remove it from the system? No.
It stores mulm, fish feces, and other junk, and is a place where those substances further metabolize and can leach invisible, chemical substances back into the water.
Unless the aquarist purges the media of this stuff, it is still in the system, and still in the tank, unless removed by water changes, or some other chemical reactor, or substance.
In my filtration plant work, biological filters needed to be backwashed every 5 days, otherwise non-beneficial bacteria would proliferate, and particles would break through, which lead to a lessening of filter efficiency.
I believe some kind of similar routine needs to be done on aquarium filters.
This leads to another question…
My water is perfectly clear, doesn’t that mean it safe?
No.
Most of the substances that are toxic in either an acute way, or chronic way to our fish, are invisible.
And just because an aquarium is cloudy, doesn’t mean its unsafe.
Anyone that lives next to the Mississippi river knows, the water can be mud brown and still be teaming with fish.
