7.3. Media Volume

If one works all the numbers on biofiltration media in the aquarium filter you come up with two very interesting tables.

The first table is based on the well established fact that ammonia oxidation needs 5 square feet of effective biomedia surface area per pound of fish.

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)	16	12	8	4	2
30 ppi foam in canister or sump	25	18	12	6	3
30 ppi powerhead operated sponge	25	18	12	6	3
30 ppi foam air-operated sponge filter	29	22	15	7	4
Plastic pot scrubbers	31	24	16	8	4
Static K1 media	33	26	17	9	5
20 ppi foam in canister or sump	33	26	17	9	5
20 ppi foam powerhead sponge filter	33	26	17	9	5
20 ppi air stone sponge filter	38	29	19	10	5
Powerhead operated under-gravel	62	46	31	15	7
Aquarium gravel in canister or sump	62	46	31	15	7
Air-operated under-gravel filter gravel	72	54	36	18	9
Blue Matala pads	72	54	36	18	9
1/8-inch garden pumice or perlite	86	65	43	22	11
Bio balls	86	65	43	22	11
Alfagrog	108	81	54	27	14
1/2-inch lava rock	144	98	72	36	18
Seachem Matrix	144	98	72	36	18
Biohome Ultimate	216	162	108	54	27
Ceramic rings	216	162	108	54	27
Ceramic balls	288	216	144	72	36
Expanded clay pebbles	288	216	144	72	36

Biomedia Volume ONLY ammonia oxidation

If one wants crystal clear water and healthy fish, ammonia oxidation is only a small part of the story. For heathy fish and crystal clear water one wants at least 100 square feet of surface area per pound of fish. This gives a considerably different table.

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)	320	240	160	80	40
30 ppi foam in canister or sump	500	375	250	125	63
30 ppi powerhead operated sponge	500	375	250	125	63
30 ppi foam air-operated sponge filter	580	435	290	145	73
Plastic pot scrubbers	620	465	310	155	78
Static K1 media	660	495	330	165	83
20 ppi foam in canister or sump	660	495	330	165	83
20 ppi foam powerhead sponge filter	660	495	330	165	83
20 ppi air stone sponge filter	751	563	375	188	94
Powerhead operated under-gravel	1240	930	620	310	155
Aquarium gravel in canister or sump	1240	930	620	310	155
Air-operated under-gravel filter gravel	1440	1080	720	360	180
Blue Matala pads	1440	1080	720	360	180
1/8-inch garden pumice or perlite	1720	1290	860	430	215
Bio balls	1720	1290	860	430	215
Alfagrog	2160	1620	1080	540	270
1/2-inch lava rock	2880	2130	1420	710	355
Seachem Matrix	2880	2130	1420	710	355
Biohome Ultimate	4320	3240	2160	1080	540
Ceramic rings	4320	3240	2160	1080	540
Ceramic balls	5760	4320	2880	1440	720
Expanded clay pebbles	5760	4320	2880	1440	720

Biomedia volume CRYSTAL CLEAR water

Most of the media represent what a media will do in a canister, sump or hang-on-back filter. We’ve added 30 ppi and 20 ppi sponge filters and an undergravel filter gravel as media.

It has to be emphasized that these tables apply for fish fed at a 1.5% feeding load of typical commercial dry fish food. This is typical for adult fish. Obviously if one uses a 3% feeding (juvenile fish) load will require twice the media. If you feed your fish per the directions on most fish food containers (“what they can eat in five minutes three times a day“) you will need like ten times the media.

Depending on what your goals are for your aquarium, only ammonia oxidation or crystal clear, healthy water, one can now calculate the media needs for any given aquarium. The only missing piece is the weight of the fish.

One surprisingly accurate way to tell the weight in grams is to multiply the length by the width by the height in inches (I know, we’re mixing measurement systems but that the rule!).

We will use what researchers have found. Researchers have compiled lists of the weights of very many fish and set up an equation to calculate the weight of the “average” fish. Using the equations and correction factors a table is easily set up for the “average” fish.

Length Inches	Length Centimeter	Weight Grams	Metabolic Weight Grams
1	2.54	0.32	1
1.25	3,18	9.64	2
1.5	3.81	1.1	3
1.75	4,44	1.8	5
2	5.08	2.5	7
2.25	5,72	3.73	10
2.5	6.35	5.12	14
2.75	6,98	6.81	18
3	7.62	8.86	22
4	10.16	21	47
5	12.7	41	82
6	15.24	70.5	113
7	17.78	112	140
8	20.32	167	167
9	22.86	239	239
10	25.4	328	328
12	30.48	581	581

The “metabolic” weight reflects the fact that small fish swim much more than large fish, burn up far more calories, and thus give a lot more bioload per gram of fish than do large fish. But note this has to be tempered by the shape of the fish and how active they are.

A wide bodied fancy goldfish can weigh three times what its length says it should weigh. A slow moving catfish will only have the actual weight, not the metabolic weight. Surprisingly tall fish like discus and angelfish are only twice the weight of a similar “normal” fish shape. But also note that long flowing fins like a guppy has have to be ignored in the length calculation. All these considerations makes knowing the actual weight kind of a guessing game.

If one were starting out and put together a typical aquarium with a bottom to top flow hang-on-back filter, what would be the minimum amount of each type of biomedia one could have?

Let’s assume the stocking was a community aquarium with three 3″ angelfish, two bristle nosed plecos, and one opaline gourami. Because the angelfish are tall one has to multiply 22 by 2. So three angelfish are 132 grams, a 4″ bristle nosed pleco is only 21 grams because he moves very slow, and one 4″ opaline gourami is 47 grams. This is 132+21+47 = right about 221 grams.

Let us say you have a bottom to top flow hang on back with 10 inches by 2 inches by 8 inches of room for media. That is 160 cubic inches (10 x 2 x 8). What will be the media you can use for ONLY ammonia oxidation with 221 grams of fish? Note the gallons of water and GPH is immaterial.

So the chart goes to this:

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)
30 ppi foam in canister or sump			12
30 ppi powerhead operated sponge
30 ppi foam air-operated sponge filter
Plastic pot scrubbers			16
Static K1 media			17
20 ppi foam in canister or sump			17
20 ppi foam powerhead sponge filter
20 ppi air stone sponge filter
Powerhead operated under-gravel			31
Aquarium gravel in canister or sump
Air-operated under-gravel filter gravel			36
Blue Matala pads			36
1/8-inch garden pumice or perlite			43
Bio balls			43
Alfagrog			54
1/2-inch lava rock			72
Seachem Matrix			72
Biohome Ultimate			108
Ceramic rings			108
Ceramic balls			144
Expanded clay pebbles			144

HOB 220 gms only ammonia

Ammonia oxidation is EASY and all the media in an HOB will do the job for this 200 gram fish aquarium.

Now let us say that we have the same situation: a bottom to top flow hang-on-back with 160 cubic inches and roughly 221 grams of fish. What is the media which will give us CRYSTAL CLEAR, BACTERIA FREE, HEALTHY WATER?

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)
30 ppi foam in canister or sump
30 ppi powerhead operated sponge
30 ppi foam air-operated sponge filter
Plastic pot scrubbers
Static K1 media
20 ppi foam in canister or sump
20 ppi foam powerhead sponge filter
20 ppi air stone sponge filter
Powerhead operated under-gravel
Aquarium gravel in canister or sump
Air-operated under-gravel filter gravel
Blue Matala pads
1/8-inch garden pumice or perlite
Bio balls
Alfagrog
1/2-inch lava rock
Seachem Matrix
Biohome Ultimate
Ceramic rings
Ceramic balls
Expanded clay pebbles

HOB 200 gms crystal clear

That’s right: there is NO media which will give crystal clear water with a typical moderate loading of fish and a typical bottom to top flow HOB filter.

Doing some other situations:

So let us say you have an aquarium with a fully grown 11 inch Oscar that weighs over 450 grams (about one pound). And you have a large canister with 700 cubic inches (3 gallons, 0.4 cubic feet, 11 liters). What media will give you crystal clear water that will keep hole-in-the-head at bay?

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)
30 ppi foam in canister or sump	500
30 ppi powerhead operated sponge
30 ppi foam air-operated sponge filter
Plastic pot scrubbers	620
Static K1 media	660
20 ppi foam in canister or sump
20 ppi foam powerhead sponge filter
20 ppi air stone sponge filter
Powerhead operated under-gravel
Aquarium gravel in canister or sump
Air-operated under-gravel filter gravel
Blue Matala pads
1/8-inch garden pumice or perlite
Bio balls
Alfagrog
1/2-inch lava rock
Seachem Matrix
Biohome Ultimate
Ceramic rings
Ceramic balls
Expanded clay pebbles

Biomedia Amount of One Oscar

Per the above only 30 ppi foam, plastic pot scrubbers and static K1 media will give an Oscar complete freedom from the POSSIBILITY of hole-in-the-head syndrome. Note the gallons of water in the aquarium and the GPH are immaterial.

So let us say you have an aquarium with 123 grams of fish. And you have a canister with 700 cubic inches (3 gallons, 0.4 cubic feet, 11 liters). What media will give you crystal clear water? Per the below all media except Biohome and ceramic rings will do that. Note the gallons of water in the aquarium and the GPH are immaterial.

Biomedia	454 grams fish	370 grams fish	247 grams fish	123 grams fish	62 grams fish
Fluidized K1 (60% loading in sump)
30 ppi foam in canister or sump				125
30 ppi powerhead operated sponge
30 ppi foam air-operated sponge filter
Plastic pot scrubbers				155
Static K1 media				165
20 ppi foam in canister or sump				165
20 ppi foam powerhead sponge filter
20 ppi air stone sponge filter
Powerhead operated under-gravel
Aquarium gravel in canister or sump				310
Air-operated under-gravel filter gravel
Blue Matala pads				360
1/8-inch garden pumice or perlite				430
Bio balls				430
Alfagrog				540
1/2-inch lava rock
Seachem Matrix
Biohome Ultimate
Ceramic rings
Ceramic balls
Expanded clay pebbles

Biomedia Amount 123 grams Canister

Again, it has to be emphasized that these tables apply for fish fed at a 1.5% feeding load of typical commercial dry fish food. 1.5% is typical for adult fish. Obviously if one uses a 3% feeding (juvenile fish) load will require twice the media.

An Illustration

Here is a comment to this web page (https://aquariumscience.org) and its answer:

And you can add fish right away and just not feed them for a few weeks or wait literally as long as you are comfortable with. I add pond mud (see the article on the “mature aquarium”) and wait at least six weeks minimum but I’m a little nuts.

Another Example of Aquarium Filter Media Calculations

This exchange is from the comments section of this website (https://aquariumscience.org):

A other one:

These examples illustrate the process very well.

Sump Considerations

If one is doing the calculations for a sump one should be aware that fluidized bed K1 is roughly 58% more efficient than static 30 ppi foam as far as filtration. The effective surface area considerations are that fluidized K1 is 900 square feet per cubic foot of media. At 60% loading this becomes 540 square feet per cubic foot of sump filter.

Foam with 30 pores per inch has a surface area of 340 square feet per cubic foot. 540/340= 1.58

Still another illustration:

Further Research

There are some aquarium hobbyists who are interested in delving deep into the science and the calculations behind all aspects of the hobby. For those who are so inclined the following is pertinent:

7.6. Required Aquarium Filter Media Surface Area