Wednesday, July 31, 2013

Every day I get e-mails but this one e-mail has some very good questions…

Every day I get e-mails but this one e-mail has some very good questions that are probably asked the most frequently of all hobbyists, especially the newer ones that buy a Biofalls filtration system.

Dr. Novak

I met you at the Webb's house this last weekend and we spoke about Anoxic Filtration.  I have a few questions. 

1) I have several plants in my pond currently should I change over to the cat litter/Laterite mixture at this point?  Will that help?  I will not be able to dig a Anoxic Filtration system until mid fall.

2) My pond is about 4000 gallons and I currently use a skimmer that has a brush filter with a Matala blue filter mats in front of that.  Should I keep that in place?

3) I have a waterfall with bio balls in place it is about 2 foot deep.  Should I replace that with a pot with litter/Laterite?

4) Can I keep what I have in place and just add the new filter system to my pond?  Do they counteract each other?

Thank you,


Biofalls filters clog very easily and are too small for most ponds. Very restricted in how much water can go through them,too.

Photo taken from internet.

Question 1: If you have several plants potted up incorrectly, then yes by all means replant then in Biocenosis baskets. There are two good reasons why: One, the Biocenosis baskets can get acclimated and use the bacteria off your plant roots to become established. This will make cycling time much shorter instead of the 45-50 day it takes to establish a Biocenosis basket. Second, the plants themselves must get use to working for their food by taking in ammonia instead of Nitrogen. As you may well know all plants when transplanted except maybe Mums, will go into a shock and then spend most of their energy developing a root system. The warmer pond water will help accelerate the bacteria growth better than in the cooler waters of autumn.

Question 2: The skimmer your currently using should stay in place. A good skimmer before the Anoxic filter is paramount for lower TDS, CE and a higher redox. Sounds to me like you have a good skimmer already and you don’t have to replace it or upgrade.

Question 3: I’ve talked about biofalls filters in the past and they are always overrated on what the can accomplish in ones pond. Good for garden ponds only but not for Koi or heavily stocked Goldfish ponds. So, get your Biocenosis baskets all set up then in late August sometime take everything out of the biofalls and replace with Biocenosis baskets if you like or leave it empty. Most people will only place Water Hyacinth in their empty biofalls for cosmetic reasons.

Question 4: Keep your prefilter and have it go to your Anoxic filter but you don’t have to remove your old biofalls filter if you don’t have to, that’s up to you. However, do not run that filter (Leave it empty; see question 3 for more info.) with an Anoxic filter because it is such a counterproductive filtration system. If you said you had a Nexus filter for example I would say keep it and run that one too. Biofalls filters are nothing more than mechanical filters that clog too easily and sway hobbyists into believing they have done something good when they really haven’t because of clogging.

Furthermore, they are just too high in maintenance, and people tend to get lazy with them and won’t clean them as often as they should. If Biofalls are not cleaned regularly then TDS will rise and redox will fall. Just because the turbidity of the water looks clean ,doesn't mean you have good water quality. An Anoxic filter needs to be cleaned twice a year only with a good pre-filter before it, but a Biofalls filter  no matter what kind of pre-filter you're using  should be cleaned once a month and/or more often in peek pounding season when detritus, fish waste and smuts are at their worst. To me, Biofalls filters are a new hobbyists nightmare because they are never told the truth when they buy them.

The two photos above are only a small part of WEBB'S filtration system. Nexus filter had no air going to it and the K1 was not moving. We alerted someone and they found the airline had broken.

Anoxic Filtration System by Syd Mitchell, Tony Ruiz & Dr Kevin Novak

Meanwhile, there is another question I would like to ask...

Meanwhile, there is another question I would like to ask. In the beginning of your article you explained about the nitrification process from ammonia to nitrite then to nitrate. And the mistake of most hobbyist of neglecting the danger of accumulating nitrate. From here I got the idea that the main purpose of the Anoxic Filtration system was to break down nitrates by taking the oxygen away and leaving the nitrogen to go free to the air. Meaning that the Anoxic Filtration system is still an integral part of the already existing nitrification process. So if I put it into my pond system the flow will be as follow:
Mechanical filtration:
 Here the solids that might clog the bio filters are separated and backwashed daily.
 Here is where ammonia is converted in to nitrite
 Here is where nitrite is converted in to nitrate
 Anoxic Filter:
 Here is where nitrate is stripped from oxygen and releasing nitrogen thus completing the cycle

I’m sorry if I got the chemistry wrong here. But, somehow from the later parts of your articles I got the impression that the Anoxic Filtration system is a standalone system, not needing the two previous biological steps (Ammonia to nitrite and nitrite to nitrate). All it needs before entering the system is a good mechanical filter. So which is correct, my initial assumption or my latter conclusion?
One more question. About the plants to be planted in the baskets, do we have to plant them? What would be the benefits? What would I be missing if I didn’t plant any? I am looking forward to as minimum maintenance as possible. Okay Dr.Kevin Novak, again thank you very much for your kind assistance. I will be taking photos of my pond later today, and will send it to you along with the kitty litter experiment result to help give you a better picture of my pond.
Best regards,

This photo was take by me from a waterlily growing in an Anoxic filter without fertilizer tabs. Now what hobbyist wouldn't want this in their garden or Anoxic filter? This beautiful flower is what you would be missing if you left plants out of an Anoxic filter. Look at the colors, absolutely breathtaking!


The difference from that of an Anoxic filter and conventional filter is the Anoxic filter does not make a waste product like the bacteria in the Nitrogen cycle does. Either plant and/or bacteria utilize as a food source from all available ions. As you stated in your outline, biofilters 1&2 both produce a waste product that another bacteria has to consume as a food source. The Anoxic filter can do all that and then some with a specialized bacterium without the dependency of a highly oxygenated medium to live on.

 If the bacteria in biofilters 1&2 begin to clog or if a hindrance of oxygen were to become an issue, then that bacterium would suffer, and its ability to carry out the Nitrogen cycle would be compromised. A compromising of bacteria is not even a risk with the Anoxic filter, which is good if you have Koi 20" or longer and overcrowding is an issue and for some reason oxygenation of the pond is stopped or lowered oxygen levels in solution.  Your Koi may suffer but not the bacteria in the Biocenosis baskets.

Each biocenosis basket acts like a giant magnet that attracts ions (positive ions) out of solution; I explain that in my blog. So the nitrogen cycle as you know it and have explained, is not relevant with the Anoxic filter. High oxygen loving bacteria are not its primary reliance; that is only with conventional filtration.

In fact just this weekend I was at someone house looking at a Nexus 300 filter and when the lid was opened the K1 medium was not moving at all and the airline going to the Nexus was broken. How long was it broken, is anyone guess. It just goes to show you that accidents do happen and if for some reason the hobbyist does not check their equipment every day the nitrogen cycle will become compromised very quickly. Not so the Anoxic filter, because all you have to do is get water from point A to point B and if the ion flow stops for some reason (as illustrated in my blog what happen to a hobbyist in the UK) the bacteria will utilize another food source for dinner and its oxygen requirements.

Plants are an option as shown in my blog but all Anoxic filters that are outside benefit from plants. From a cosmetic point of view, WAF (Wife acceptance factor) and taking in cantons and anion out of solution. Not only does the Anoxic filter give you a water garden look with plants in it but also a fancy goldfish pond in the summer months...You can’t put little fishies in a Nexus filter, unless they like hurricane conditions.

I personally like plants but I also like big fat Koi too and it seems like the two don’t mix very well in ponds unless the plants are protected from the hungry Koi. Well, now the Anoxic filter gives you some options; plants or no plants, Koi and/or Goldfish.

Anoxic Filtration System by Syd Mitchell, Tony Ruiz & Dr Kevin Novak

Saturday, July 27, 2013

With A Little Foresight The Mucerino’s Will Save Money On A New Expanding Pond Project This Year.

This is a raised-bed Anoxic landscaped stone filter built in 2009 by the Mucerino's ( a father and son project) and is shown in my iBook. The filter can be drained from the bottom automatically and refilled by just turning a valve. Water is being pumped in from the bottom and diffused there so no exterior pipes are showing. This Anoxic filter is filtering a 6000-gallon pond that’s 18´ X 18´ by 5´ deep with two waterfalls spilling out 8000-gph going back into the pond.

Now after four years (2013) it’s time for a modification to the pond this year. They will make the pond longer and deeper. However, the Anoxic filter will not have to be touched, it’s big enough to handle a larger pond with no problems. They are now going to add another bottom drain that’s bigger in diameter (It looked to be 6" diameter) with an air diffuser attached to it and sloping the bottom of the pond to aid the new drain. The sloping of the bottom will aid in water circulation and getting the fish waste out easier. The only new pieces of equipment they are going to add to the system is a Clarity Filter and one more skimmer.

If this was a conventional filter instead of the Anoxic filter, you would have to buy all new equipment are add on some more very expensive filtration equipment to do the same job as the Anoxic filter. In fact, this is exactly what happens to homeowners all the time when they wish to expand their old ponds into larger ones. They soon find out that all that money they spent on filtration equipment is not going to be adequate enough to handle a larger pond. Therefore, another expense must be added to the modification budget. I’ve always believed in: Do it once and do it right the first time! Adding Biocenosis basket to an existing Anoxic filter is cheep and easy to do. I like technology, but sometimes it can break the bank or stymie a new pond build project with overinflated cost.

Raised-bed Anoxic filter with two streams coming out of it.
The colors of these Koi are very vibrant and they just pop-out at you.

This photo shows the skimmer and when pond is made larger another one will be added. It's hard to believe you can have a pond this beautiful for very little outlay.
Anoxic filter with some Water hyacinth ( E. crassipes) floating  in it. No aquatic plants are in the Biocenosis baskets themselves, they remain bare. For those that say this is a Veggie filter or Bog filter, this is proof that it is not plant dependent at all. The Biocenosis baskets look like they are covered with a sheet of glass it's so clear.

From the skimmer all detritus goes into the bead-filter (That's cleaned once a week.) for one more cleaning before water goes to the 55-watt UV Light, then the clean water heads to the Anoxic filter and back into the pond. Look at the photo above and see how clean the Anoxic filter is because of this fantastic pre-filtering system that the Mucerino's have. Too many people say the filter will get all full of smuts, but that's not true if you have a good pre-filter before the Anoxic filter. Clean water goes in and cleaner water comes out.

Anoxic Filtration Book... Still free on Apple's iBook store 

Wednesday, July 24, 2013

Just my viewpoint.

Just my viewpoint.

As we all know that because of commerce this hobby thrives and it has nothing to do with science per say. After all the science in ponding hasn’t changed in decades it has just become more expensive to own. I have personally gone to see some of the top places that build ponds for homeowners in my area to help them relearn how to plant up aquatic plants instead of using garden center planting pots and topsoil. Only to be told they are constantly at meetings all the time and would get back to me. Well guess what; they never did!

Biocenosis Clarification Baskets are for everyone not just those that use an Anoxic Filter. But then again if they told you about Biocenosis Baskets, then maybe they wouldn’t sell you all those chemicals and plant tabs. Nevertheless, they maintain that they are here to teach the hobbyists’ on the subject of ponding; yet close their own doors when it comes to them learning what science has to offer. How can you teach anybody anything new, when you refuse to learn it yourself? That is unless it will cost the consumer something…then they’re all for it!

Tell me if you owned a business and you could find a better way that could help that business in an already hurting industry (An industry that has lost a lot of business lately and not just because of economic woes.), wouldn’t you like to know if something out there could help business and give you a economical edge over your competition? 

 So remember the next time someone tries to sell you their products, it’s only because of money and not the betterment of the hobby. They can care less if you or your animals live or die. All they want to do is sell you another product to compensate for that inadequate product they sold you in the first place. I know it’s not their fault, they don’t make the bad products; they only sell them. Let’s face facts, its only business and your money is as good as anyone’s out there. Profit margins have to be big, are there’s no interest at all in just science! That bottle on the shelf makes money, not sound advice without a sale. I think the old saying goes: We will pay for bad misconstrued advice, but we will not take good advice for free.

I think it’s a sad state of affairs when money dominates over the betterment of the hobbyists: Don’t you think? There are a lot of good products out there and some very upscale technology to go with it. I love techno stuff myself and enjoy its company, but with that said, I also must think: Can I accomplish the same results at lower costs and be more efficient in doing so? After all not everyone goes out and buys a Rolex watch just to tell time do they? Techno gear comes in pretty packages and has a lot of advertisement behind it but somebody has to pay for that advertisement. I can’t tell you how many expensive canister filters made by reputable manufactures I have in the attic that did not perform up to par and hit the filtration graveyard, but yet each one claimed to be the best thing out there.  

I can say this however: With ponding... my money was well spent on the information science gave me and not what some moneymaking advertisement told me to buy. That’s my two cents worth. 
A pond with an Anoxic Filtration System during MPKS pond tour 2013. I count 22 Koi in this photo alone and that's only about half of the Koi that take up residency in this 6,000-gal pond.

Anoxic Filtration System by Syd Mitchell, Tony Ruiz & Dr Kevin Novak

Sunday, July 21, 2013

Part 3: No plant fertilizer tabs are to ever be used in a Biocenosis Basket ever!

Part 3

If you were wondering why you should not use any nitrogen tablets in the Biocenosis basket, it is because plants must get their nitrates into their cells against an electrical gradient. Plants, algae, and all photosynthesizing organisms use the N (NH3 and NH4+) of ammonium, not nitrates, to produce their proteins. Using nitrates is costly to the plant in terms of both electrons (e-) and energy. Because NH3 is a small molecule (NH3 ammonia enters plants even more easily than NH4+ ammonium) without an electrical charge, it freely diffuses back and forth across the cell membrane barrier.

The energy required is so substantial for the plant that nitrates are only taken up in the daylight (during photosynthesis) whereas considerable ammonium uptake will continue in the dark, all night long, long after photosynthesis has stopped. The fact is, or pond plants do not begin the process of photosynthesis, until the sun begins to rise. However, it is not unusual for plants to begin photosynthesis until as late as 11:00a.m. only for this process to peak around 2:00p.m. in the afternoon, then slowdown at sunset. After the process of photosynthesis can no longer take place, the plants will begin to generate carbon dioxide instead of oxygen. The plants do not have as much time to deal with excessive nitrates in solution, as you would think.

The energy used represents about one-fourth of the energy required for the plant to produce its carbohydrates. Photosynthesis is reduced by one-third in the conversion of each nitrate to ammonium, in a two–step process of nitrate reduction; the plant for increase growth and flowering could use this energy. The fact is none of our aquatic plants needs nitrates as a food source only ammonium, and there are only a few exceptions to this rule, one is Eichornia Crassipes (Water Hyacinth), with 75 percent of its food source being nitrogen and 25 percent being ammonium. Aquatic plants potted in compost, humus or topsoil endowed with organic matter will certainly grow luxuriantly. However, excess nutrients that leak into solution from such media will lead to the eutrophication or as it's called hypertrophication of the garden/Koi pond. This state of affairs arises from an over supply of plant nutrients in solution that favors the growth of algae at the expense of vascular plants.

Laterite or clay (Kitty litter) has a crystalline structure attracting cations (positive ions like k+, Ca+++, Mg++, Al+++). If other growth factors are present in reasonable amounts, (Note; this is called the Liebig Minimum Law) you will have good root growth. By good root growth, we do not mean many roots. You can have hardy plants with big, thick masses of roots in other systems. What we mean here is root hairs in proliferation filling up a planted pot. The more proliferation of root hairs, the better the plants uptake of cations (positive ion) and anions (negative ion) out of the water body proper. The adsorption and absorption, or in equal equilibrium between anions and cations is very important. If anions where taken into a plant without cations in equivalence, any plant would suffer from a fatal pH swing. Repeatedly it has been observed that the uptake of nitrates from pond containing both ammonium and nitrates only starts after ammonium has been exhausted or its concentrations greatly reduced.

This is what I mean (the two photos above) by good root growth and root hairs in proliferation filling up a planted pot and this is only after a few months.

Research has shown that even the type of pots and baskets that are used play a very important part in this filtration system. One of several experiment that were conducted, was to take two different kinds of plant containers, one was a pot you may get at any nursery center with holes only at the bottom of it; the other was the open-cell- plant basket. The pots and baskets where planted up with Acorus Calamus (Sweet Flag). Kitty litter and Laterite were both used as a substrate. The pots and baskets were then submerged into a pond with an oxygen content of no less than 8mg/l. There was to be a grow-out period of four weeks for the plants to become established. After four weeks, the pots and baskets were to be removed from the experimental pond for examination, for their oxygen content, plant growth, root development, and bacteria growth.

It was discovered that the pots that only had the holes at the bottom of them already smelled like hydrogen sulfide. Assimilatory Denitrification by sulfate reducing bacteria and methanogenic bacteria were present, oxygen levels were between .5mg/l- 0mg/l as tested. The open-cell baskets smelled sweet , meaning that there was still oxygen but at low levels (between 1.8mg/l-.5mg/l). The plants in the open-cell baskets were already showing good root growth. The plants in the pots that only had holes at the bottom of them showed very little to no root growth at the time.

(Part 4)

(Part 2)

(Part 1)

Anoxic Filtration Book... Still free on Apple's iBook store

Friday, July 19, 2013

Anoxic Filter Build By: Brian Woodcock in the UK. Part #5

Old photo of planted-up Anoxic Filter.

This is his newest photo of Anoxic Filter and of the new plants. Do you see whats missing? The Clarity filter...looks a lot better now! For those that think an Anoxic Filter is nothing more than a Veggie filter...Brian doesn't have enough plants to do the job like a Veggie filter. So, and Anoxic Filter can be a Veggie filter but a Veggie filter can never be an Anoxic filter.

This is an E-mail from Brian letting me know how his Anoxic Filter is doing in the UK.

E-mail Quote:

“Hi Kevin, a bit of an update you might be interested in. My nitrate has gone from 80+ppm to 40ppm in the short time my anoxic filter has been running, also I removed my Clarity-type filter and was expecting an ammonia spike with keeping to the same feeding regime...but no sign if either ammonia or nitrite so I’m a very happy chap :)

An added plus is my plants are doing great.”

Anoxic Filtration Book... Still free on Apple's iBook store

Thursday, July 18, 2013

Anoxic Filtration Q&A from Dr. Franco’s blog in Italy.

Anoxic Filtration Q&A from Dr. Franco’s blog in Italy.

Translation by Google 


 The laterite is all divided into small piles of equal weight (about 385g) according to the number of baskets that you have to fill in, then the baskets are filled up to 4 cm from the top and should be given with your hands a depression in the center. You must enter the laterite in the depression and should be covered with litter (always supplied in adequate quantity) to standardize the level with that move.
Finally should be placed pebbles (quarry) by 2-4 cm above the litter coming up to completely cover the top edge of the plastic basket.


The litter basket contains a fine powder that must be removed before the introduction of baskets in the pond (the risk is that the color of brown or grey aqua).  To this end it is sufficient to immerse every basket a couple of times in a basin containing water, dripping after a few seconds can be introduced into the filter.


No, the nitrification filter produces classic, starting from ammonia, nitrite and then nitrate in a process called "nitrification", which is part of the "Nitrogen Cycle", while facultative anaerobic bacteria use their ability to process ammonia directly when they find it as such, but must convert ammonia to nitrite and then if the nitrogen comes in the form of nitrate, they must do the exact opposite route.

This subjects the bacteria to more metabolic work which slows down the unique ability to use ammonia directly.

If you want to go during the hot season, a filter to a classical filter anoxic nitrification, as a precaution and only you can do initially coexists two types of filter, taking care to place the filter before the anoxic nitrification and not the other way. If the replacement takes place over a period of quiescence of the filter (winter), the substitution can be so fundamental without risk to the fish.

4)  HOW LONG WILL IT TAKE TO BE THE FILTER Anoxia 100% efficient?

In ponds already built and launched it takes about 20 days.  In lakes started, where initially they coexist (for security reasons) two filter systems (anoxic nitrifiers and classic), the activation time may be considerably longer, but not more than 50 days.

5)  I CAN MAKE A FILTER Anoxia And Add The Laterite Later?

No, the laterite plays an important role as a mineral deposit to which the bacteria facultative anaerobes draw for their optimal development and replication. The laterite is a mineral rich sediment of many substances used by bacteria for their metabolism such as iron hydroxide, iron oxide, zinc, copper, manganese, cobalt, kaolin (which is a white clay containing aluminum oxide, titanium oxide silicon), traces of inorganic elements, just to name a few.


Dr. Novak has spent more than 20 years to test an infinite amount of clay that may have an effect similar to that of clay litter. None of those tested has the characteristics of porosity and permeability of this.  Dr. Novak for the realization of the anoxic filter has previously rejected as bentonite clay, montmorillonite, kaolin, Uras, Illite, sepiolite, attapulgite.


No, the filtering capacity of the basket depends on water that passes close under the action of a water circulating pump.  At the bottom of the pond baskets would not have enough flow with which to interact to subtract the nitrogenous contaminants.
In addition, the baskets would be placed directly on the bottom soon the subject of curiosity koi who love digging gravel in search of food, the natural consequence of finding the empty baskets and the litter scattered on the bottom of the pond.


No, the baskets have drilled 6 faces exposed to contact with the water that would not have if you would put directly to the litter on the bottom of the pond.  The filtering capacity of the basket Biocenosis would thus be undermined.


. In ecology the term biotic communities (or communities) is derived from Greek words βιος (bios = life) and κοινος (koinosis = common) and indicates the community of species in an ecosystem that lives in a certain environment, or, rather, in a particular habitat (from the Greek life and τοπος βιος = = place), ie an area in which the physico-chemical and environmental conditions are constant. The habitat, due to its characteristics, can be defined as the fundamental unit of the environment. Wikipedia The ecosystem is made up of biotic and habitat so. Wikipedia

Biocenosis The basket is therefore a unit in which bacteria cooperating in the formation and maintenance of a certain chemical and physical environment and environmental conditions constant.


The bedding material is a clay fired at high temperatures through which the clay micro-porous structure assumes its importance. Nearly over 20 years of use since it was discovered for use in the anoxic filter has not shown signs of functional decline. The laterite is a mineral rich in trace elements that are used by bacteria for sustenance and ripodouzione.  This source is exhausted after approximately 10 years and must be replaced by another new one that is added directly into the basket that contains the old litter.


Yes, the baskets can contain all types of aquatic participant whose capacity is added to that specific filter basket Biocenosis. . Depending on the type of trees planted in the baskets, the water level of the basket to the surface of the lake varies from 2-3 cm to 10-20 cm.  The baskets that contain plant given the vigorous growth of the latter, the presence of laterite, be repotted at least every 2 years.


They can be arranged in several rows side by side and overlapping, making sure to put a spacer between the baskets and the bottom of the filter (of an inch, minimum) and between baskets placed one above the other. Horizontally baskets, given the shape of a truncated inverted pyramid can be matched to each other without spacers.


The baskets can be of different sizes: 23x23, 28x28, and 32x32 (not marketed them in Italy) would be natural to say to add as many baskets until the water reaches the correct values stability.
 Since it is never a problem to put more than needed, to put the minimum number depends on the size and number of fish in the pond.
Conventionally, a basket of 28x28 can filter water from the waste produced by 
an adult koi no more than 40 cm.  the calculations for the other baskets are to be calculated on the basis of this finding, and in any case, if the values ​​are not yet fully achieved, it is necessary to add additional baskets.  
Biocenosis Basket in an Anoxic Filter in Italy byDr. Franco for his experiments.
Club meeting Dr. Franco had to introduce the Anoxic Filter to the Italian hobbyists. 

Wednesday, July 17, 2013

Setting up and testing the Anoxic Filtration as told by dkoinut on 2009.

Setting up and testing the Anoxic Filtration as told by dkoinut on 2009.
   Hi Dave: I have been using Kevin's Anoxic filtration system for over one and a half years, closer to two tears now and I believe I gave it an honest test. My pond is one of those pictured in your reference. I'm still using the Anoxic filter and am very pleased with it. I was a little leery at first because it took so long for my Anoxic filter to get up to full effectiveness, but I was way over stocked, too. I also wanted to really abuse it to make sure it would do as he stated.
   I clean the anoxic filter and drain it twice per season; March and October. I only did 60% water changes spring and fall. 25% this year so far. Also I only replaced water used in flushing my bottom drain, and what was lost thru evaporation. I did this to abuse this filter to make sure it would keep up with my fish load. I currently have 26 Koi ranging from 10 to 28 inches. From standard charts, I calculate a conservative 69-pounds fish load. Until late last summer the load was much higher. I sold and gave away over 65 8 to 12 in Koi, and 8 in the 20 to22 inch range. I believe I also over feed my Koi I went through 175-lbs of Koi staple pellets last year plus shrimp, many fruits, rice, night crawlers, silk worms, etc. My water quality has remained very stable. Much more so than when I used DIY up flow filters 440 gallons of them).
  Update as of 10/2008 from my water quality testing log-" After using the Anoxic filtration system for 1-1/2 seasons, I am convinced that it works very well as described by Kevin. And I'm very satisfied with mine. My water quality has remained very stable last year. And even with my very minimal water changes/additions. pH 7.9 to 8.1 regardless of time of day; 0.0 ammonia; 0.0 Nitrite; and nitrate has continued to drop to less than 5-ppm. I did a large 50% water change at start-up in March and otherwise, less than 2% per week till October. I did this as an extreme test, Next year; I'll probably do more 5 to 10% water changes." I believe this system is very effective on my "over stocked koi pond". It did take longer to completely remove nitrites. 05/07 to 05/08. Like all Koi ponds, this filter needs clean water, so a pre-filter/mechanical filter is a must. I would also say that labor requirements were reduced by at least 50%. There are 3 pictures of my pond and filter in Dave’s reference link.
  My first is the rectangular concrete block pond. It’s actually a bit over 7000 gallons. Then there are 2 pictures of my Anoxic filter. I tried to copy/past but the photos wouldn't come thru. Anyway, they're about 3/4 down on the first page. I just got my greenhouse cover off the pond yesterday, but did clean the filter pond last month. Marsh Marigolds are blooming up a storm and the water irises are also growing like crazy. Most of these systems mine included are flow thru so cleaned and filtered water flows from the filter pond to the Koi pond.
The Anoxic pond is, 5.4’ wide by 9.4’ long and 28 inches deep, and about 915 gallons. I have the bog plants on elevated platforms. And there are a total of 54 biocenosis pots, with about 20 planted. Way more than is required. My water lilies and other plants bloom nonstop all summer and grow like crazy. I have to repot after 2 years, or the plants will destroy the pots and all without adding commercial fertilizer.

Setting up and testing the Anoxic Filtration System by: dkoinut

   In my case, I had a very heavy fish load from the start. I didn't get the filter pond completed until August 2007 and had readings of ammonia and nitrite for remainder of the summer. I thought the filter would cycle in 4 to 6 weeks as my sand and gravel filters had done. I didn't get zero readings until the end of May or early June of 2008.  This was my fault for assuming faster cycling and for not having other bio filtering on the pond at that time. My Koi ranged from 8 to 28 inches at that time. Since this was a test I did very few water changes or additions as this plus having a plant pond were my 2 main concerns with this filter. 

  I consider myself a dedicated Koi hobbyist but most of my friends are water gardeners and don't want to spend too much time on pond maintenance and water changes, so the test was to see how well this filter would work. And for me the answer is exceptionally well, once it's cycled (Ed: The system will take at least 45-days to cycle.). And it is also very important to provide the cleanest water possible. That is no or very little suspended wastes particles since the filter is only cleaned 2X per pond season. My pond in the CD photos is the concrete block pond. It is to be hoped that I'll get the tile or stone on to make it more presentable this year. This filter should work very well for your pond. Good luck and have fun. There is a lot of talk on about the filtration system you may wish to look at. 

(Ed: It has now been over 6-years now and Darrell is still using the Anoxic Filtration System with others following his lead in Iowa.)

Darrell's Anoxic Filter at the end of the summer with Iris 6' tall.

Anoxic Filtration Book... Still free on Apple's iBook store