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.]