# a story



## pop (Aug 29, 2012)

I woke up this morning to find abandoned orphan aquarium bundled on my door step!
There was a note “take care of her” I read as I decided to give her a home. I read on, new aquariums need to have filters that will keep her clean. So began the search for the right filter for my baby.
I quickly learned at the local tank outlet, the right filter could be determined by how many times the water column passes threw the filter. This flow rate can be slow or fast depending on the type of set-up and number of water critters contained in the aquarium. 

Filter manufactures use these flow rates in terms of gallons per hour in which a slow flow rate would move the water column threw the filter 2 to 4 times every hour and faster flow rates would move the water column threw the filter 5 to 10 times every hour. This does not have much meaning due to the size of the tank the filter will be attached. Consider a filter that has a flow rate 240 gal per hour attached to a 30 gal tank would produce a very high flow rate while the same filter on a 55 gal tank would produce a much slower flow rate. (Side bar: My assumption that manufactures determine flow rate with functional media and head pressure may or may not be true. Therefore gph in actual gallon per Hour could be alternately represented when rating test are conducted using only the pump output without filtering media present or equivalent head pressure).

Resulting in ambiguous understanding of flow rates or currents created by filter return.
These filter created currents are important factor that holds unwanted waste in suspension so the mechanical media of the filter can catch the waste. This prevents biological produced waste from accumulating on top of the substrate. Though once captured this biological waste continues to pollute the water column and must be removed in order to lower the levels pollution.

There are basically three different ways to filter aquarium water. Mechanical, chemical and biological and each form has advantages as well as disadvantages.

When considering mechanical filtration the notion of efficiency is a very elusive characteristic because mechanical filtration is the capturing waste particles from the water column. A disadvantage of this form of filtration is that not all of the particulate matter is captured. Flow rate has an impact on the filters efficiency; most mechanical filters pushes water with too much velocity threw the filtering medium splitting some of the particulate matter into smaller and smaller pieces increasing the total suspended solids (TSS) in the water column. 

As the velocity of the flow rate increases the greater is the reduction in size of the suspended particulate. These micro sized particulate will free flow threw the media until particulate accumulation begins to slow the flow rate at this point the micro particulate will begin to be collected. In this process the filtering medium is starting to clog reducing the rate of flow while at the same time increasing the efficiency of the medium in catching suspended micro-particulate. With the results of particulate of certain size and density will settle out of the water column due to the loss of support by the ongoing slower current.

When considering mechanical filtration one must think about effective pore size. This is the average pore size of the smallest particulate contained by the filtering medium and not passed through the media back into the water column. Any arrangement of filter medium such as floss, sponges or grids, micro-porous sheets, gravel, sand or smaller grain material will have an effective pore size. 
Mechanical filtration should start with media pore size larger than the optimum porosity because it is understood that with use the medium will begin to clog and more efficiently capture finer particulate. 
Water polishing is the forcing the water under pressure through micron medium (very small pore size) removing the smallest suspended matter. 

Mechanical filtration is open-ended process that is defined by the particle size of the waste to be captured. The more filter medium in the filter the greater is the potential for capturing the waste and the finer particle size captured the more waste is caught and held. So adding more filtering media beyond the optimal amount affects the filter cleaning scheduled more than increasing waste removal.

Mechanical filtration removes visible waste from the water column by containing waste in the filter media; it will not remove the pollutants from the water column. These captured wastes still contribute to the bio-load and will continue to pollute the water column.
It’s important to remember that all biological waste is not visible.
(Side bar: water column refers to the visible water between substrate and surface of the water only and doesn’t include diffused water in the substrate or filter).

Many fish keepers have a veiled view towards chemical filtration; firstly it is said this type of filtration is a waste of both time and money. Yet these same folks will secretly use this method as temporary measures or emergencies only and would not consider incorporating chemical filtration into the daily aquarium filter system.


Chemical filtration media collects impurities from the water column and the most common medium used for this purpose is activated carbon. The broad spectrum capabilities of carbon to adsorb diverse variety of dissolved chemicals while resins are targeting a single impurity such as phosphates for removal. Chemical filtration immediately removes these impurities from the water column and are active until the media becomes saturated then must be changed out to renew chemical filtration. (Side bar: after the media ceases to adsorb it often provides an environment for significant bio-filtration from bacterial colonies).

The notion that chemical filtration can only last for a short time is not necessarily correct. The life time of the media is limited by type and amount of media and the concentration or the total mass of each dissolved material to be capture. Chemical filtration has limits in terms of volume. Activated carbon (AC) or granular activated carbon (GAR) should be made from bituminous coal which is highly porous. Chemical filtration by active carbon only happens through direct contact between the carbon surface and the water surface in-contact with the carbon. There is no wicking through the carbon media everything is surface contact. 
The most visible effect of active carbon is the removal of dyes and colorants. Over time most established aquariums the water column tends to turn yellow from natural biological processes increasing total dissolved solids. Total dissolved solids from wood, peat moss or bogwood are adsorbed by active carbon increasing the clarity of the water column. This clarifying process has the added advantage of positivity affecting all living plants.


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## pop (Aug 29, 2012)

*contine story*

Many tropical fish keepers with live plants hold the view that active carbon will adsorb necessary elements from the water column such as chelated iron and copper. Active carbon will adsorb these and other non-chelated minerals and can be off-set by adding some micronutrients and chelated minerals to the water column. Other fish keepers hold the view that activated carbon will release back into the water column collected impurities using the example of a sponge soaking and then releasing liquids but this is not how activated carbon operates. Activated Carbon adsorbs pollution and can not release captured (adsorbed) materials in a home environment. The advantages of activated carbon filtration can almost be provided by regular and frequent partial water changes that dilute the contained pollutants instead of removing potential pollutants.
Bio-filtrations is the most valuable type of filtering because the bio filter actually cleans the water through bacterial processes that consume the toxic substances that naturally develop in the closed system of the home aquarium. Mechanical and chemical filtration capture and hold contaminates for removal by the fish keeper but biological filtration occurs naturally without intervention by the fish keeper. Biological filtering provides clean and less toxic water creating a thriving environment for our water critters. This process is known as nitrification which is part of the nitrogen cycle. The nitrogen cycle begins with nitrogen being removed from the air and is completed when the nitrogen is returned to the air as inert gas. In the home aquarium nitrification is the establishment of beneficial bacteria colonies.
Bacteria live everywhere in our aquariums with various species that feeds on ammonia produced by both fish metabolism and organic decomposition. Beneficial bacteria require highly oxygenated waters with nitrogen availability in ammonia and nitrite form to establish colonies. The porous filter media is the ideal environment for all bacteria to colonize, ample flow of pre-filtered water providing abundant oxygen and nutrients including un-oxidized metabolites ammonia and nitrite. Even though biological filtration is a natural process it needs to be protection from silting and suffocation caused by settling of suspended particulate accumulation.
Bacterial colony size is determined by two limiting factors the availability of in-tank production of nitrogen metabolites and highly oxygenated water in slow flow. So this process is concerned with the oxidation of nitrogenous waste produced by the normal metabolism of water critters. Fish release ammonia into the water column through their gills. This form of ammonia has the greater affinity for water of any element in the aquarium. Active transportation of this material across the gills is not necessary. Simple osmosis the diffusion from area of high concentrations, from fish’s blood, to the area of low concentration the water column is all that is needed. 

Where these nitrifying colonies are established is up to you the fish keeper who created the initial filter set-up and the way the aquarium upkeep is preformed. This positive relationship with nitrifying bacteria lolls us into forgetting that bacterial colonies are not stagnant but are dynamic in the terms of population growth. Bacteria receiving nitrogen metabolic matter and oxygen will not just metabolize they will multiply. This steady state population is always changing and renewing population. Because nitrification is an acidifying process it will affect the carbonate/bicarbonate buffering of the water column and associated pH, both should be monitored.

Today the aquarium filters offers benefits unknown to earlier fish keepers yet they still need to be maintained on a regular basis. Aquarium filtration can not remove waste from the tank. Mechanical filtration will capture particulate, bio-filtration change metabolites from one dissolved toxic form to another less toxic form and chemical filtration captures and holds specific pollutants, so is out of sight out of mind? NO!! 

All particulate that is captured or altered through filtering devices are still present in some form and continually in intimate contact with the water affecting water quality until we fish keepers removes the contaminates during periodic filter maintenance. Both TDS and TSS are diluted with each partial water change.

What does this mean to me and my orphaned 29 gallon aquarium it means that I will incorporate the different filtering types into three separate filtering mechanisms creating my own SLOW FLOW filtration system. I plan to establish a sand substrate that will be the bio-filter providing nitrification, air driven sponge filter for mechanical filtration and the aquarium came with aqua clear 70 hang on the top filter as chemical filtration.

Purple Possum Rides at MIDNIGHT

DISCLAIMER: I stood on the shoulders of these giants for this view of filtration.


SOURCES
Angels plus.angelsplus.com,Web.7 Aug.2013<Understanding Aquarium Filtration>
Tropical Fish Hobbyist Magazine.tfhmagazine.com.Web.7 Aug 2013<Filtration | Aquarium Basics | Tropical Fish Hobbyist Magazine>
Aquariumlife.aquariumlife.net.Web.8 Aug 2013.<Aquarium Filtration (AQUARIUM CARE ARTICLES)>
_Schiff, J. Steven.”Undergravel filters: Maintance and Altervatives”fishchannel.com.Web,8 Aug 2013<_Undergravel Filters: Maintenance and Alternatives>
Admin.How to choose aquarium filter,1 Feb 2013.petskeepersguide.com.Web. 8 Aug 2013<How to Choose an Aquarium Filter - Pets Keepers Guide>
Ricketts, Robert T ”Filtration Basics: Part One, introduction, current and mechanical filtration” badmanstropicalfish.badmanstropicalfish.com. Web.8 Aug 2013<Aquarium Filtration Basics: Part 1, Introduction, Current, and Mechanical Filtration>
Ricketts, Robert T ”Filtration Basics: Part two chemical filtration” badmanstropicalfish.bad,manstropicalfish.com. Web 8 Aug 2013<http://badmanstropicalfish.com/articles/article71.htm>
Ricketts, Robert T ”Filtration Basics: Part three: Biological Filtration” badmanstropicalfish.badmantropicalfish.com. Web. 8 Aug 2013<http://badmanstropicalfish.com/articles/article72.htm>
Ricketts, Robert T ”Filtration Basics: Part four: Getting it all together and keeping it there”.badmanstropicalfish. badmanstropicalfish.com.Web.9 Aug 2013. <http://badmanstropicalfish.com/articles/article73.htm


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## Hallyx (Jun 11, 2011)

Enlightening post. What I find most interesting is his conclusion regarding which filter does which job. This is stated as his "intention' but it's really his conclusion. Anyway....

I would think that the sponge filter, with it's large fine-pore filter media would be a natural for housing a bacteria colony. The higher flow HOB would suck in and hold more suspended particulates, seems to me. And I remain to be convinced that there is enough exposure of the nitrogen compounds to their oxidizing bacteria in a sand or gravel substrate, notwithstanding there may be more (gross) bacteria in the substrate.


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## pop (Aug 29, 2012)

Hello Hallyx:

As jaysee has said you can’t actually separate the different filtering process, they occur as natural process happening in the aquarium. what i was proposing is a conceptual view of these processes. by breaking down the combined filtering function into individual conceptualized parts allows me to view and use each process to my best advantage. It helps me understand what is going on in my aquarium.
Convincing anyone to the value of this conceptual construct is not my goal. I only posted this to learn and understand what goes on in filtration. 

You my friend sound a little wolfish are you planning to huff & puff and blow all of my cognitive constructs down. as long as conversation is friendly and good natured with the intention of learning HUFF AND PUFF BLOW ALL OF THEM DOWN!!! 
a good argument to begin with is THE WHOLE IS GREATER THAN THE SUM OF IT’S PARTS meaning the act of segmentation of the parts loses an important aspect of the whole that can not be found in the individual segments. :-D

POP


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## Hallyx (Jun 11, 2011)

Couldn't agree with you more, pop. And I understood the segmenting of filter types as a way to illuminate the parts of which the whole is greater than their sum..

Your allusion to my "wolfish" tone absolutely cracked me up. Were I a faster and more facile typist, I could schmooze and banter and take the edge off my tone. My terse and spare style primarily derives from my lack of ability as a typist, less my capabilities as a communicator. 

But thank you for pointing that out.


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