What is SSA (Specific Surface Area)?

[John Russell]

Hello all,

I've been asked "What is SSA - and why is it so important?"

Specific Surface Area, or SSA for short, is the available surface area of any type of filtration media per square foot that nitrifying bacteria can live on. A biological filter, no matter what type or brand, is designed to house media that nitrifying bacteria live on in a bioflim for the purpose of metabolizing ammonia and waste from pond water.

The two primary forms of bacteria that make up the nitrification cycle within biofilters is Nitrosonomas and Nitrobacter. As most of your already know, Nitrosonomas bacteria convert ammonia to nitrite, and the Nitrobacter strains of bacteria convert that nitrite to nitrate. There are other strains of heterotrophic bacteria and enzymes that participate on the over all nitrification cycle as well.

The bacteria live on the surfaces of what ever type of media is inside the biofilter in what is called the "biofilm layer". The higher the SSA, the more bacteria that can live within the filter, thus the higher the SSA, the more ammonia and waste that can be metabolized. SSA is the base figure used to calculate how much fish waste and ammonia that a biological filter can metabolize in a 24 hour period. SSA is the common denominator across all biological filters and media. It is the "Horsepower & Gas Mileage" rolled into one easy to understand number.

"All biomedia in fish pond filters or bio filters of any type can be classified according to its specific surface area (SSA). The higher the SSA the more probable is it that the biomedia will be more effective in a fish pond filter. SSA refers to how much surface area per unit volume of a type of media is available for colonization by bacteria inside fish pond filters."
Excerpt from www.clean-garden-ponds.com/biomedia.htm


Virtually all media manufacturers publish the SSA of their biofilter media. For example, Matala publishes the SSA of each of their filter pads on their web site. Their pads SSA's range from 10.33 to 28.5. Polyflow publishes on their web site the SSA of their filters pads ranging from 31 to 49. Bioballs range from 16 to 21 SSA, lava rock averages 14.35 SSA, Springflow strapping type media ranges from 10 to 15 SSA, pot-scrubbers range from 55 to 80 SSA, HydroFiltersilk has a 61 SSA, plastic and foam beads range in SSA from 60 to 80 SSA, Kaldness has a 41 SSA, and bio-tube media has 125 SSA. There are many other types of media also that I haven't listed here as well. All media has measurable surface area, and SSA commonly refers to how much total surface area the media has per square foot of that media.

All biological filters contain media. All media has measurable surface area.

It is impossible to know how many fish a biological filter can support, and how much fish waste and ammonia the biological filter can metabolize without knowing its SSA. SSA tells you how much nitrifying bacteria can live on the media - the biofilm layer as it is commonly refered. You don't know how much gasoline your car burns without knowing the Miles Per Gallon (MPG) - well, SSA is the same type of critical number to know.

It is commonly known, and widely published in study after study that it takes an average of 10 square feet of biofilm (SSA) to metabolize 1 gram of phyiscal fish waste per 24 hours. It takes and average of 50 square feet of biofilm (SSA) to metabolize 1 gram of ammonia per 24 hours. Fish, including koi, produce an average of 33% of their total body weight in waste per 24 hours. Fish, including koi, excrete .1 grams of ammonia per 1,000 grams of body weight per 24 hours. These statistics are compiled from State Fisheries, University Aquaculter Studies, Hatcheries, Breaders, and Human Food Fish Farmers.

SSA tells you exactly how much biofilm a biofilter contains. The SSA then tells you how much ammonia and waste it can metabolize in a 24 hour period. Once you know the maximum amount of ammonia and waste the biofilter can metabolize, you can calculate how much fish, by weight, produced the waste and ammonia.

For example: A biofilter with a Total SSA of 2,000 can metabolize 200 grams of fish waste per day. (2000 SSA x .1 = 200) That 200 grams of fish waste was created by 600 grams of total fish weight. The 2000 SSA tells us that it can metabolize 40 grams of ammonia per day. (2000 SSA / 50 = 40). The weight of the fish, 600 grams, tells you that you can feed the fish 21 grams of fish food per day. (Fish, including koi, consumer and average of 35% of their total body weight per day, thus 600 grams of fish weight x .035 = 21)

So to sum up. SSA (Specific Surface Area) is the total amount of space for biofilm colonization within a biofilter. The SSA number tells you exactly how much ammonia and waste in can metabolize per day. The total waste tells you have much fish, by weight, made it. The total weight of the fish tells you how much food to feed the fish per day. Without knowing the SSA of your biofilter - you can only guess as to fish loading and feeding.

SSA tells you how much fish your biofilter can effectively support.

Thanks so much for the question.
Sincerely,
John Russell
President/CEO Russell Watergardens

[schildkoi]

Let's go through these in a little more depth if you do not mind.

Quote: Hello all, I've been asked "What is SSA - and why is it so important?" Specific Surface Area, or SSA for short, is the available surface area of any type of filtration media per square foot that nitrifying bacteria can live on. A biological filter, no matter what type or brand, is designed to house media that nitrifying bacteria live on in a bioflim for the purpose of metabolizing ammonia and waste from pond water.

Absolutely correct but the "catch" is in the word "can" in the sentanece ending in "that nitrifying bacteria can live on." This often times gets misconstured as to "will" live on. The relationship is actually much deeper. This surface area mus be kept free of debris and detris. It is also dependent on the nutrients (ammonia in this case) suppiled to that surface area. The biofilm reactions are instananeous as its relates to the conversion of ammonia to nitrite PROVIDING that the ammonia molecules come into close enough proximity to the biofilm itself.

Quote: The two primary forms of bacteria that make up the nitrification cycle within biofilters is Nitrosonomas and Nitrobacter. As most of your already know, Nitrosonomas bacteria convert ammonia to nitrite, and the Nitrobacter strains of bacteria convert that nitrite to nitrate. There are other strains of heterotrophic bacteria and enzymes that participate on the over all nitrification cycle as well.

Yep, no problems there.

Quote: The bacteria live on the surfaces of what ever type of media is inside the biofilter in what is called the "biofilm layer". The higher the SSA, the more bacteria that can live within the filter, thus the higher the SSA, the more ammonia and waste that can be metabolized. SSA is the base figure used to calculate how much fish waste and ammonia that a biological filter can metabolize in a 24 hour period. SSA is the common denominator across all biological filters and media. It is the "Horsepower & Gas Mileage" rolled into one easy to understand number.

Now here is where the relationship is often misinterpreted. Above you draw the conclusion that the more surface area available, the more bacteria can live within the filter. This is not necessarily true if that surface area is not maintained and IF the nutrients are not supplied in close enough proximity to that biofilm/surface area.

Quote: "All biomedia in fish pond filters or bio filters of any type can be classified according to its specific surface area (SSA). The higher the SSA the more probable is it that the biomedia will be more effective in a fish pond filter. SSA refers to how much surface area per unit volume of a type of media is available for colonization by bacteria inside fish pond filters." Excerpt from www.clean-garden-ponds.com/biomedia.htm

It is more prbable within that given design but not directly relational from one design to another due to the factors (cleanliness of the filter and rate at which the nutrients are supplied to such).

Quote: Virtually all media manufacturers publish the SSA of their biofilter media. For example, Matala publishes the SSA of each of their filter pads on their web site. Their pads SSA's range from 10.33 to 28.5. Polyflow publishes on their web site the SSA of their filters pads ranging from 31 to 49. Bioballs range from 16 to 21 SSA, lava rock averages 14.35 SSA, Springflow strapping type media ranges from 10 to 15 SSA, pot-scrubbers range from 55 to 80 SSA, HydroFiltersilk has a 61 SSA, plastic and foam beads range in SSA from 60 to 80 SSA, Kaldness has a 41 SSA, and bio-tube media has 125 SSA. There are many other types of media also that I haven't listed here as well. All media has measurable surface area, and SSA commonly refers to how much total surface area the media has per square foot of that media. All biological filters contain media. All media has measurable surface area.

My sources at Evolution Aqua quote a surface area per cubic foot of Kaldness to be as follows:
1 cubic feet of Kaldness = 274 sq ft of surface area
I am not sure of your other SSAs' are correct or not

Quote: It is impossible to know how many fish a biological filter can support, and how much fish waste and ammonia the biological filter can metabolize without knowing its SSA. SSA tells you how much nitrifying bacteria can live on the media - the biofilm layer as it is commonly refered. You don't know how much gasoline your car burns without knowing the Miles Per Gallon (MPG) - well, SSA is the same type of critical number to know.

Even knowing these factors you cannot adequately determine how much fish/waste a filter will metobolize iunless you can also determine the ongoing cleanliness of the media, the flow rate and it ability to pass the nutrients in close enough proximity to the biofilm itself.

Quote: It is commonly known, and widely published in study after study that it takes an average of 10 square feet of biofilm (SSA) to metabolize 1 gram of phyiscal fish waste per 24 hours. It takes and average of 50 square feet of biofilm (SSA) to metabolize 1 gram of ammonia per 24 hours. Fish, including koi, produce an average of 33% of their total body weight in waste per 24 hours. Fish, including koi, excrete .1 grams of ammonia per 1,000 grams of body weight per 24 hours. These statistics are compiled from State Fisheries, University Aquaculter Studies, Hatcheries, Breaders, and Human Food Fish Farmers.

Again, I'd like to see those studies since again, wiothout knowing the other factors the measurement quoted is a "guess" at best.

Quote: SSA tells you exactly how much biofilm a biofilter contains. The SSA then tells you how much ammonia and waste it can metabolize in a 24 hour period. Once you know the maximum amount of ammonia and waste the biofilter can metabolize, you can calculate how much fish, by weight, produced the waste and ammonia.

SSA Does NOT tell you exactly how much biofilm a biofilter contains. Again, there are other influencing factors.

Quote: For example: A biofilter with a Total SSA of 2,000 can metabolize 200 grams of fish waste per day. (2000 SSA x .1 = 200) That 200 grams of fish waste was created by 600 grams of total fish weight. The 2000 SSA tells us that it can metabolize 40 grams of ammonia per day. (2000 SSA / 50 = 40). The weight of the fish, 600 grams, tells you that you can feed the fish 21 grams of fish food per day. (Fish, including koi, consumer and average of 35% of their total body weight per day, thus 600 grams of fish weight x .035 = 21)

Once again, that is within a perfect filter, one maintained clean, free of all debris, all of the time, and passing all nutrients within the prescribed proximity range.

Quote: So to sum up. SSA (Specific Surface Area) is the total amount of space for biofilm colonization within a biofilter. The SSA number tells you exactly how much ammonia and waste in can metabolize per day. The total waste tells you have much fish, by weight, made it. The total weight of the fish tells you how much food to feed the fish per day. Without knowing the SSA of your biofilter - you can only guess as to fish loading and feeding.

Its a starting point for a perfect world, again not a hard measurement that is true in any/all situations.

Quote: SSA tells you how much fish your biofilter can effectively support. Thanks so much for the question. Sincerely, John Russell President/CEO Russell Watergardens

Once again, its a starting place and an estimation at best. When this number is misconstrued, it can lead to disaster. Let me4 give a couple of examples from your website: http://www.russellwatergardens.com/pondstyle.htm

Quote: Since the traditional koi pond doesn't' have the added surface area that gravel, rocks, and plants provide - the filtration systems are usually larger - with much higher volumes of surface area for bio-film colonization. They are designed to remove waste as it falls to the bottom of the pond through bottom drains instead of relying on bacteria colonization at the pond bottom to break down the waste. They usually have a UV in the system to help keep the water clear of free floating algae that would turn the water green because of their lack of plants that aid in starving out algae.

Now John, we both know that gravel in the bottoms of ponds collect waste. Anyone who has ever had to clean one realizes how detroimental this can be to ANY koi, not just those that you say wish to be kept at optimum health. This waste is not totally broken down and in fact collect at what I personally would consider a high rate over a rather short time span. Now you talk in the paragraph above about added surface area due to the rocks themselves for added biofilm. Since this surface area (rocks) is not maintain in a clean condition and there is virtually no water movement overthem, the little added surface area is actually negated as compared to that of a smooth sided koi pond is typically less.

As for Koi pjnd filtration, most advanced hobbyists learn the value of highly oxygenated bio-chambers. Most are under the misunderstanding that the aoration is provide for O2 within the chamber. This is in actuality a negligable effect. The real positive effects are a) it keeps the surface area clean by reducing/eliminating the ditrus build up on the media thus allowing the biofilm a clean surface and keeps that biofilm from becoming strangled so to speak by these solids. It aslo, b) increases the currents within the chambers creating multiple passes of the water column through and around the media increasing the likelihood that the nutrients will pass within close enough proximity to the biofilm.

So although you explaination of SSA is factual, your application of such, particularly on your website is misconstrued.

As for the "raking" of the rocks? Well, that is a practice that I wouldn't recommend since it releases waste and gases back intot he water column that could very well be detrimental if not lethal to the koi. Also remember one simple principle. Whether rasing a koi that is a family pet, or raising a grand champion, the environments for a helthy koi remain the same.

Steve Childers

[Russell Peters]

I started in on the same path you took, but decided it was too much effort....and for what. Thank You.

[Nancy M.]

Quote: Originally Posted by Russell Peters I started in on the same path you took, but decided it was too much effort....and for what. Thank You.

I would have tried to explain it, but that would have been a joke.. Thank God we have our expert in pond design and filtration Mr. Childers.
Excellent post Steve

[bekko]

John, you should fake an injury and try to sit on the bench as much as possible because you are playing out of your league.

Quote: All media has measurable surface area, and SSA commonly refers to how much total surface area the media has per square foot of that media.

The web site you referred to measures SAS in square meters of surface area per liter of volume. That's how the Europeans do it. In the US, engineers use square feet of surface area per cubic foot of volume when comparing filter media. It has been done that way for at least sixty years. Measuring surface area per square foot of media makes no sense since the media is three-dimensional. Matala can get away with it because they have a standard mat thickness. But, how deep is a square foot of Kaldnes? I don't know where your numbers came from, but they are very non-traditional. The least you can do is provide units of measure.

Quote: The two primary forms of bacteria that make up the nitrification cycle within biofilters is Nitrosonomas and Nitrobacter. As most of your already know, Nitrosonomas bacteria convert ammonia to nitrite, and the Nitrobacter strains of bacteria convert that nitrite to nitrate.

Well, actually they are finding that you can not attribute nitrification to these two species alone. Nitrosomonas (not Nitrosonomas BTW) is often not even a dominant ammonia autotrope in many systems. The current terminology is to just call them nitrifying bacteria and leave it at that.

Quote: It takes and average of 50 square feet of biofilm (SSA) to metabolize 1 gram of ammonia per 24 hours.

That is a good number to use for design purpses. However, the reported range in the aquaculture literature is 0.1 to 3.0 grams of total ammonia nitrogen (TAN) removed per square meter of biofilm per day. That equates to 4 to 110 square feet of biofilm per gram of TAN removal per day. Removal rate is a convenient way to approach the issue, but the background level of TAN is also an important consideration. At higher background TAN concentrations the removal rate is higher, but the background concentration may be unacceptable from the standpoint of fish health.

Quote: Fish, including koi, produce an average of 33% of their total body weight in waste per 24 hours.

Where did you get that number? Assuming that the fish is not growing and all of the feed is converted to waste the feed rate would have to equal 33% of the fish body weight per day on a wet-weight:wet-weight basis. Thus, the weight of dry pellets fed daily would equal about 10% of the fish's body weight. A fry can eat that much, but by the time a koi is large enough to sell it will not eat more than about 2% of its body weight per day.

In designing a filtration system, it is customary to work from the maximum amount of feed to be added each day - not the number or weight of the fish. For a biofilter, nitrogenous waste is the primary concern. The dominant source of nitrogen is protein in the fish feed. The feed bag will tell you the protein content - typically 32 to 40%. Protein contains 6.25% nitrogen. Ammonium (NH4) is 82% nitrogen. Therefore, each gram of 36% protein feed will be converted to 0.03 grams of ammonium (36% x 6.25% / 82%).

Quote: These statistics are compiled from State Fisheries, University Aquaculter Studies, Hatcheries, Breaders, and Human Food Fish Farmers

Mrs. Paul and McDonalds are my favorite fish breaders and I've been immersed is aquaculture R&D for a very long time. If you're serious about this stuff then you should do more homework. Do literature searches for publications by Tim Pfeiffer, Mike Timmons, Tom Losordo, Bjorn Rusten, John Colt, Ron Malone, Ep Eding, Phil Lee and Shulin Chen. Shulin Chen has focused on foam fractionators but is well versed in all aspects of aquaculture water treatment. I mention Dr. Chen specifically because he is right there at Washington State University, Pullman Campus. Give him my regards.

-steve hopkins

[mitten]

The advantage of a thick skull is that when something does get through it is seen in a shining light. All of the preaching and all of the soap boxing always comes around to this as the Truth...Get the poop out fast.

This is the real reason for no rocks, This is the real reason for bottom drains, aeration in the pond, TPRs, sloped bottoms, and the Coolest Stuff...Vortexes, properly sized for PASSIVE mechanical filtration.

Bio filtration is easiest. All you need is a bare liner, some pipes and a stream in some cases. When you have efficient passive mechanical seperation of wastes which are removed easily and daily, all bioloads are diminished and biofilters can work at peak efficiencies because they are dealing with dissolved wastes not turds.

Mickey the windowman

[PapaBear]

Much thanks to SteveC and SteveH.
I was wondering when the Square foot measure vs. Cubic foot measure was finally going to find its way into the discussion. This topic, if well hashed out, could provide an excellent resource for pond builders/designers seeking better information on biofiltration calculations than a lot of what is out there. Hard number calculations seem to work a lot better than mythology.
As to the fish weight vs. feed weight debate, in the case of a hybrid type pond I'd much rather go with the 1/3 fishweight waste production model in this instance, even though it isn't accurate. In a hybrid setting full of plants (decaying veggie matter) and turd laden gravel being "fluffed" into a cloud of bile, the SSA calculation needs to "go long"

[dOHd]

Quote: I started in on the same path you took, but decided it was too much effort....and for what. Thank You.

Russell, What is too much effort? And for what?????

d

[schildkoi]

You do measure surface area as Square ft since "area" is NOT 3 demensional. BUT, you measure sq ft of surface area per a volume (3 demensional) of media (cubic ft).

Steve

[jnorth]

Quote: Originally Posted by dOHd John, What is too much effort? And for what????? d

That was Russell Peters that said that and not John Russell.