So the experiment was to keep a plastic 6-mill cover over the AFS all season long and at the end of the year at the October cleaning see just how much detritus really would accumulate inside the filter.

If you have been reading some of the pond and Koi forums out there some know-it-all hobbyist(s) advocate that the AFS is nothing but a cesspool of muck and detritus. If not cleaned like other filters more than twice a year you will end up with all kinds of bacteria problems and water degradation along with sick fish.

These are the same people that know nothing about the AFS, have never read about it or become the self proclaimed aquatic microbiologist that really contribute nothing to this hobby except misguided information to others. Their real agenda is never really understood by most but one thing is for sure:  If an audience will listen then they will preach their sermons on that proprietary knowledgeable soapbox forever.

Despite the fact that I have said it several times before the AFS really doesn’t get that dirty if a proper prefilter is use before any pond water goes into the filter. Plus the fact that any detritus that does settle in the AFS never really gets compacted like filters that pass water through a medium, unless pond maintenance is forgone far too long. Most turns into mulm by a chemical reaction called oxidation anyway by the end of the season and becomes inert.  This loose layer of mulm is nothing to worry about and is unsightly but nonetheless is a natural process of life in a pond.

It may consist of cat litter that has migrated out of the BCB’s, dead cyanobacteria, algae, and geographic pollution from outside sources.  This could be from birds, trees and just dust and dirt that is airborne getting into the filter itself. All of what I have said sounds very logical if a well designed prefilter is use before the AFS. I mean, how else would the filter get dirty?

This year I did an experiment to see just how much dirt and detritus would really fill an AFS if all outside insults were lessen or eliminated altogether. This experiment would show that the amount of detritus would basically be plant and/or bacteria origin related and basically the AFS does stay very clean from one cleaning to the next.

As we know the BCB’s do not clog so that’s one less thing that has to have servicing throughout the year like other filter need. So the experiment was to keep a plastic 6-mill cover over the AFS all season long and at the end of the year at the October cleaning see just how much detritus really would accumulate inside the filter. Basically the filter would be a greenhouse for the aquatic plants with four 6" (152.4mm) holes in it, two on each side.

As everyone knows I have nothing but a homemade prefilter for my pond. Nothing expensive bought out of a box and is serviced once a week during high feeding season and once every fortnight when only feeding once a day. The cover has been on since last cleaning in May of 2014 and was remove in October of 2014 to be evaluated for mulm or detritus accumulation.

You can see the very bottom of the filter that it has cat litter on it by the red arrow. A thick layer of all kinds of mulm or detritus is not covering it up. The lowlight short hair alga seen is because my filter is under a Snowdrift crabapple tree that is very messy. With over 50 trees  in the yard, birds, squirrels, leaves and everything else get into the filter every year, but one thing that doesn’t get into the ponds filter is sunlight. 

 In October all aquatic plants are cut down and the filter is emptied and cleaned for the winter months ahead. This gives the Koi fresh water and a nice new clean environment for their long winters nap.

What I found out was, there was very little mulm or detritus in the filter this year at all! Once the outside insults were lessen to a greater degree the AFS remained very clean despite what some think. Most of what did exist was plant related along with a little Goldfish waste, but was nothing to get upset about. I was really quite a surprised at just how much outside pollution gets inside an AFS. If pond husbandry is carried out on trimming any dead or dying plant foliage then pollution inside the AFS is very negligible.

You also must remember that algae and cyanobacteria are part of the equation of pollution that gets inside an AFS and dies and then is broken down into mulm. Plant DOC’s are really nothing to worry about unless in excessive amounts. In most ponds the DOC’s come from animal related insults about 90% but not so much plant matter. If you can control the amount of insult getting into an AFS then the cleaner it will be between seasonal cleanings.

Part two: The Answer..Your DOC’s are being introduced through your Bakki Shower Filter, but not your Sand filter.

PART TWO: ANSWER

Your DOC’s are being introduced through your Bakki Shower Filter, but not your Sand filter. First, your Sand Filter once it starts to clog, as stated in your letter, Quote: “but whenever it is clogged and need backwashing the foam would be significantly less or none at all.” begins to act like a micron filter or Diatomaceous Earth Filter by “polishing” the water and removing some of the DOC’s in the process. Once this happens it will even strip fish slime right out of the water too.

This is why Sand Filters remain so popular today if filtration Husbandry is kept up on them they can reward the hobbyists with very Gin clear water. The sand itself being inert, chemically speaking has micro pores but they are just too small in size to be of any concern.

I do not understand why the changing of the sand is recommended, if cleaned, and because it is inert and will not clog because of the micro pores are so small: Why change something that never wears-out?

The interaction between bacteria, detritus and sand surfaces are and become material removable. By mechanical action by other apposing sand particles and this then makes an initial mechanical contact between the two surfaces to wear or clean each as ‘mechanical wear’ by interactions by impact wear of the two particles.  If you were using some of the newer sintered medias out there, then I would have to agree that replacement is a necessity because of clogging of the larger tunneling pores.

It sounds to me that someone just wants to sell you new sand and blow smoke in your eyes that it’s because it will accumulate DOC’s is not true. Maybe if it was never cleaned… but then again Sand Filters need a cleaning everyday and sometimes more than once a day at that.

Your statement, Quote: “Another "suspect" I have are the mats in my Bakki showers, they tend to accumulate mulm under them and also like you said they are covered in cyanobacteria.”  Now you found your fly in the ointment! As much loved as Bakki Showers are they do have their downfalls too.

Once again we are back to what kind of media that is used in a Bakki Shower Filter will determine its productivity in the system down the road. As you are finding out, which was discovered thirty years ago, that wet-dry filters like your Bakki Shower will produce DOC’s when clogging begins. No different than a sponge getting clog up with dirt, proteins, fats, organics along with bacteria and now gravity takes over and pushes those nutrient rich chemicals out into solution once again.

Remember what I said about filters that clog, they will at some point need servicing or they will become nutrient rich expellers of DOC’s and a producer of Ammonia too.

Activated Carbon:

This is not normally use in pond applications because of expense and the very short longevity of the activated carbon itself in pond applications. For aquarium use it serves a function of keeping such a small body of water clean but in the pond, not so! A reef tank is a very delicate balancing act of recreating the entire ocean in a small glass container and a hobbyist should not buy cheep activated carbon for those applications.

Do not confuse activated carbon with the BCB’s because they are entirely two different animals altogether. Carbon adsorptive powers holds things like coloring but does not do absorption. Absorption is when one element is exchange for another element like plants do, and the BCB’s cat litter allows them to do. The plant will exchange one ion for another ion and that then becomes absorption.

Activated Carbons on the other hand with its adsorptive abilities will take in DOC’s and holds it in its pores until exhausted. There is no ion exchange with carbon like there is with the BCB’s and your Zeolite is action the same way cat litter does. Normally Zeolite will adsorb ammonia and must be recharged again in salt water. However, with the way you are using Zeolite, that recharging process is omitted because one ion is always be exchange for another ion in the BCB’s so now it is absorption instead of the adsorption that it use to do. The BCB’s do not clog because water and detritus are not being forced into the baskets and only electrical changed ions are.

Carbon on the other hand is specifically designed with just the right pore structure to adsorb and not have an exchange process of one ion for another ion like Nitrates for example. If that were the case, what good would it do at cleaning water?

Protein Skimmers:

They will remove the DOC’s from solution by their ability to have the DOC’s adhere to the surface of the bubbles and Ozone, which will enhance this action by adding an unstable atom molecule to the O2, and turn it into O3. 

Used by some hobbyists more so than any activated carbon used. This added piece of equipment is used in the pond hobby but some think it is not a necessity if proper filtration and pond Husbandry is carried out like it supposes to be. I think a proper sized UV is more beneficial to a pond than a protein skimmer.

The Problem:

You’re not the only hobbyist out there that pushes the AFS to it limits and thinks it is a ‘last word’ filter; it is not! I have had many think that their Nitrates have dropped to lets say 10-ppm which is very acceptable levels from what they had and their water is crystal clear but the filter should be doing more.

Sometimes it will take more than a AFS to bring über water conditions for all that use it because of unknown circumstances like in your situation. Every case and every circumstances has not been played out as of yet with the AFS. Like ALL filters made for ponds there is that chance that the expectations of the hobbyist are overplayed and no matter what the cost of the filter or its media that is used, it can be pushed too far.

Over feeding seems to be the biggest culprit because the filter is just that good and the first thing hobbyist do is to (Read about Brian Woodcock’s pond build and see how much he now feeds his Koi compared to his previous filtration methods he used.) (1) again overfeed their Koi to accelerate growth.

Adding the wrong kinds of extra/external filtration(s) onto an AFS are the biggest offenders of the group also. Not that adding extra filtration onto your pond is bad, but the tradeoffs with extra maintenance still must be carried out on those filters as those the AFS did not exists. Your Bakki Shower Filter still needs to have periodical cleanings or the expulsion of DOC’s into solution is its outcome. So a very good prefilter, sometimes even a micron filter is needed before the Bakki Shower or wet-dry filtration system.

Sometimes people just want a miracle filter and expect it from the AFS and for that I have failed once again.

Reply to my post above:

Thank you Dr.Novak for the crystal clear and very detailed answer. I could never thank you enough.

I have done the maintenance to the Bakki shower yesterday and yes you are right on target. To give a better picture of my Bakki Shower (BS), it consists of 4 tiers. Each tier has an acrylic bottom with holes drilled. The top and 2nd tier holds 1 layer of Japmats. The 3rd tier has Crystal Bio on the bottom and covered with 1 layer of Japmats to prevent water dropping directly on the Crystal Bio. The bottom tier has Matala Bio Actove stones on the bottom and also covered with Japmats with the same purpose of tier 3. Below the BS is the waterfall chamber where I also have 18 BCB’s and on top of them also 1 layer of Japmats for diffusion of water dropping from above.

All the Japmats are covered with cyanobacteria and also hold within them lots of mulm. I took each mat out and hosed them clean. There was a significant drop in weight before and after I hosed them clean, showing just how much mulm was trapped in the Japmats.

[Ed: (1) One hobbyist wrote me and complained that he was feeding 360-lbs. (That’s nine 40-lbs. bags of Koi food a year.) a year to his Koi and why wasn’t the AFS keeping up with his feedings and bringing his Nitrates down.]

I believe my AFS is working because with the feeding rate I’m giving, it would not be possible to have parameters mentioned above.

PART ONE: QUESTION

Hi it’s me again. As you know lately I’ve been giving my koi heavy feeding again high protein koi food, the only constraint usually would be floating feces indicating the koi have been overfed, thus I would fast them for a day and then afterwards I would continue for a week with staple koi food. Lately I’ve noticed some foam starting to show up near the waterfall. I know this must be a sign of DOC build up, but what confuses me is that all my parameters are in check. Even last night I checked my parameters Ammonia 0, Nitrite 0, Nitrate 10 mg/l, pH 7.5, TDS 58, ORP 470, but there was still some foam showing even just a little bit.

My question is, how does this DOC accumulate in my pond even though I clean my sand filter everyday including 3 more backwashes and a daily dose of clay to coagulate fine debris in order to enable the filters to filter them out faster? I believe my AFS is working because with the feeding rate I’m giving, it would not be possible to have parameters mentioned above.

Due to this problem, again I surfed the web to further learn about DOC’s and from a reef aquarium site it was mentioned that there are no bacteria that we can cultivate to take care of DOC’s, that is why the author advises activated carbon. Here is the link and the excerpt:

http://joejaworski.wordpress.com/2008/05/09/does-a-reef-tank-need-carbon/

QUOTE:

"Don’t confuse organics with ammonia, nitrites, or nitrates. The bacteria responsible for breaking down these nutrients naturally thrive in all aquariums. Most tanks are nutrient rich and provide lots of food for these bacteria to thrive. Organics on the other hand, consists of complex metabolic compounds including phenols, organic acids, proteins, fats, carbohydrates, and hormones. To break these down, we don’t (and can’t) grow the right bacteria in our aquariums. In fact, detritus on the gravel surface and in the bottom of the sump are organic compounds that have reached such high concentrations that they fall out of solution. These particles remain inert as long as pH, oxygen, and ORP levels stay constant. Any wild swings or disruptions will trigger detritus particles to release these pollutants back into solution, causing an avalanche effect that will fuel a tank crash like there’s no tomorrow."

From here I dug deeper into how activated carbon works in solving the DOC problem, and it turns out there are several alternatives which among them were montmorillonite clay Zeolite, both of which I add daily and I use in my BCB’s as a substitute for cat litter. If so then why is this DOC still persistent in my pond. Not wanting to take any chances yesterday I added 3 bags (@1kg) of activated carbon to my pond and I suppose it’s helping because the ORP increased from average of 230-250 to 270 as last measured last night.

I’m not sure if I understood it correctly but activated carbons works similarly to a part of the BCB’s in which it has absorption and adsorption properties. In other words my BCB’s should be doing this. If not so, is there something about activated carbons that cannot be replicated by BCB’s? Is adding some activated carbon of any use in taking out DOC’s in my pond? Or is the problem just I, pushing my pond too far? Hope to receive another enlightenment from you.

Some links to Activated Carbon and Protein Bubbles.

http://anoxicfiltrationsystem.blogspot.com/2014/05/about-sand-filters-state-of-art-in-pond.html

http://anoxicfiltrationsystem.blogspot.com/2014/02/this-article-is-about-association-of.html

http://anoxicfiltrationsystem.blogspot.com/2014/02/part-2-thermodynamics-substances-bead.html

http://anoxicfiltrationsystem.blogspot.com/2013/08/we-had-seen-ponds-that-had-whitish-foam.html

After reading the link given, I regret to say I am still lost. Right now, based on measured parameters, everything is in check. ORP in fact continues to increase after inserting the activated carbon and the foam is slowly decreasing.

What puzzles me is that even though at present the ORP is getting better, the previous ORP was also in satisfactory levels (430), and never have I in the past had foam when the ORP was above 400. All other parameters were also fine. But despite all these parameters being satisfactory I was still having foam. My AFS was still relatively clean from sedimentation/solid waste.

One thing I've noticed is that this foam occurs when my sand filter is operating well, but whenever it is clogged and need backwashing the foam would be significantly less or none at all. I'm now wondering, despite my cleaning out the sand daily, is it possible for the sand in sand filters to accumulate doc's within their pores (if they have any, I have no idea)? I am overdue of changing the sand according to factory recommendation, but because I clean it everyday I figured my sand doesn't need replacing, in fact I believe the sand in the filter is cleaner than new sand which still needs rinsing of debris, but now I'm having my doubts.

Another "suspect" I have are the mats in my Bakki showers, they tend to accumulate mulm under them and also like you said they are covered in cyanobacteria. 

So here I am still lost, but the activated carbon still seem to be helping. I've browsed around comparing Zeolite vs. activated carbon for purposes of taking out doc's, it seems so far Zeolite is for taking out ammonia while activated carbons are for taking out doc's. Is this correct? Comparing activated carbon with foam fractionator, which would you advise? Again I hope this email doesn't catch you at a bad time. Hope to hearing from you soon.