Tuesday, August 27, 2013

Part 1: Once the microporous structure is gone from a filter media all you have left is the outside of that media.

Part 1

Are you thinking about building a garden/Koi pond or do you already have one? One of the main concerns of people building or already having a pond is the filtration system. Filtration is the most misunderstood part about pond keeping, but the most important part of a ponds ecological stability.  

Most people will look into a pond book, and build a filter that the book recommends or buy one from a nursery center that sells pond supplies. The filtration methods and systems that are recommended in books, and there seems to be a plethora of them like Veggie, Bogs and gravel filters, and those from nursery centers are usually too small and inadequate, with very old anachronistic technology backing them. (This technology came from sewage treatment facilities back in the 1930s.) It wasn’t until 1984 when a hobbyist named George Smit, introduces a new type of filtration to the unfamiliar U.S. hobbyist. It’s called the; “Dutch Reef Filtration System.” Far better, at least we thought, than anything that was available.  

This system uses highly oxygenated filtration material, exposed to air and water, it was coined the oxymoron: Wet-Dry Filtration Systems by the U.S. hobbyist and in pond use, it’s called a Bakki Shower filter. In this method of filtering water drips or is sprayed over the filter medium that could be plastic, stones, gravel or DLS material exposed to air. The bacteria from these particular filtration systems are able to break down ammonia 30 times faster than the same filtering material submerged under water. This particular type of filtration systems believed to be technologically superior in its ability of nitrification to the ones presently known at the time.

Even so, there were some drawbacks to these filters: They produced more Nitrogen compounds taken from the air, because our atmosphere is 78% nitrogen, that add to the inorganic load (as Nitrates) of the pond. The bacteria have to secrete a polymeric type adhesive to protect them from water shear. This takes the bacteria longer to establish itself especially if the medium is plastic in nature. Unless there is an excellent prefilter, the nutrient-rich medium will begin to catch all kinds of organic microscopic particles like detritus and therefore will begin to clog: Clogging the microporous structure of the media with organic matter turning it brown in color. Once the microporous structure is gone from a filter media all you have left is the outside of that media. This happens a lot with K1 and now the hobbyist is faced with the realization that they need more K1 than what came with their filters to begin with. It didn’t take long for the hobbyists to find out what the downsides of these particular filtration systems were…in an overabundance of Nitrates and are very inefficient at the using of phosphates. However, on pond forums this is a very debatable subject.  

These types of filtration systems can add to the cyanobacteria problem, of which many hobbyist ponds are plagued with all the time. They also warp the ecology of the ponds ecosystem, which makes the ponds eutrophic in a very short time. Saltwater hobbyists found this out too when their Live-rock would get covered with cyanobacteria from excessive nitrogen in solution. Natural ponds approximately take from 100 to1000 years to age from a Ligotrophic State to a Eutrophic State.  

Eutrophication is nothing more than excess of nutrients in concentration. When organic matter and inorganic compound levels increase in a garden pond, sometimes it can become very visible to the pond owners, as protein bubbles by a waterfall or unclear (turbid) pond waters. The turbidity of pond water begins to suffer, showing up as either green water or murky water, (a hazy murkiness look to the water, which makes the water look as if it has milk in it). The haziness is from complex organic substances like decomposing fish slime, urea, fish food, feces, dying algae, and metabolic byproducts. [Ed: Read about the hobbyist with the Nexus filter and their pond not staying clear.] Nexus are over rated and k1 is in fact not that good when it comes to dealing with large amounts of waste. 

Then add the phenols and many saprophytic bacteria that affect the fish growth rates, gills and weaken them, increasing their susceptibility to disease. These dissolved and suspended compounds makeup the biological oxygen demand (BOD), color, taste, and turbidity of water. Biological oxygen demand is the amount of oxygen used by microbes, mainly bacteria, in the oxidation of organic and inorganic compounds.  

Submerge filters are plagued with their own problems also. After initial startup, they clog within 30 days (to stop clogging, it would require a 3 micron prefilter) and you lose over 50 percent of available bacteria medium surface area. These filters are high producers of inorganic compounds and are subject to organic clogging. When they begin to clog, (water will then seek the path of least resistance) these filters begin to harvest anaerobic areas or better known as anaerobic zones. These anaerobic zones reduce nitrogen back into ammonia; this is called “Assimilatory Denitrification” . They do not convert nitrates into nitrogen gas N2 then release it into the atmosphere, as some hobbyists may think. Anaerobic heterotrophs reduced nitrates back to ammonia, and no further…period!  

They are very inefficient at the use of phosphorus for energy, resulting in abundant amounts of phosphates. The ammonia, which these bacteria make, is undetectable by hobbyist test kits. The fact is because of their inefficient use of phosphates, cyanobacteria can now take over, and it only takes 0.015-milligrams/liter to accelerate an alga spore into growing. The Merck Test Kits for phosphates will read below .015-mg/l, most hobbyist test kits will not test this low for phosphates. It is no wonder that when hobbyists do test for phosphates and their ponds are full of cyanobacteria AKA: Blue- green algae that they cannot figure out why because their test kits are reading zero phosphates.  

As you can see, making a filter work for us efficiently is no easy task. There are other filters out on the market but each one makes a byproduct that another bacterium now has to breakdown into another byproduct, and therefore adds to the inorganic load. When the organic and/or inorganic load increases therefore redox potential decreases along with TDS, one is in correlation with the other. The higher redox potential numbers correspond to oxidative states that are higher in value. Such values or states are chemically speaking, only possible when no reductive processes are taking place.  

Reductive processes are those that are known as decomposition, decay, and so forth, and means that pollution is present in the pond water. The lower the measured millivolt reading the higher the pollution that is present in the pond. If these inefficient anaerobic bacteria produce more nitrogen–based byproducts that can’t be used up by the efficient bacteria in areas that have aerobic bacteria then eventually the pond will have algae problems or in some situations sick fish.

Anoxic Filtration System ®
February 02-2005-2013
New Updated Version

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