Designing the Ultimate Filtration System

[spiff]

So, my take on this would be.. any highly aerated filter will start effecting the nitrates. Heck, maybe mine does then too. I never actually tested the output from my filter specifically to see what its doing, I only ever tested the tank water.

Very interesting. I will have to check this. My setup is a waterfall system too, its just closed versus an open system as far as exposed to the air in the room.
And the water only falls a couple inches between the containers versus the foot or so the picture indicates. Never the less, the containers are so free flowing that no water ever accumulates... this is probably the key difference. So each container is a self contained 1.5ft drop through highly aerated media before reaching the sump. I bet if i pushed fresh air through the system it would increase any capabilty to remove nitrates, but at the cost of needing to dedicate a dehumidifier to this.

It all seems to boil down to the same issue... the cost effectiveness of filtering nitrates... presuming this theory is correct, then it either takes the constant running of a high intensity light to support the plants that are filtering the nitrates, or a dehumidifier to compensate for the pushing of oxygen rich air through a trick-down filter system.

I suppose, if you had a closed air system like mine..if it was feasable to redirect the exhaust air outside, then that would negate the need of running the dehumidifier. That would still effect the cost of running a furnace or AC though... ultimately not as cheap as the cost of doing water changes instead.

If someone claims the difference is solely the media.. I'll politely remain skeptical. I'll acknowledge the differences between bio media effectiveness, but not that one will do something completely different in the same setup as media of a different type. What? Are the japanese doing some sort of molecular engineering on their media that is specifially conducive to some different sort of new type of bacteria? If not, then it has to be a matter of simply maximizing efficiency of current filters. In fact, I wouldn't doubt, that if you had a sensitive enough of a nitrate testing kit, you can probably find that all filters actually help remove trace amounts of nitrates if they're working right.

[johnptc]

So, my take on this would be.. any highly aerated filter will start effecting the nitrates. Heck, maybe mine does then too. I never actually tested the output from my filter specifically to see what its doing, I only ever tested the tank water.

Very interesting. I will have to check this. My setup is a waterfall system too, its just closed versus an open system as far as exposed to the air in the room.
And the water only falls a couple inches between the containers versus the foot or so the picture indicates. Never the less, the containers are so free flowing that no water ever accumulates... this is probably the key difference. So each container is a self contained 1.5ft drop through highly aerated media before reaching the sump. I bet if i pushed fresh air through the system it would increase any capabilty to remove nitrates, but at the cost of needing to dedicate a dehumidifier to this.

It all seems to boil down to the same issue... the cost effectiveness of filtering nitrates... presuming this theory is correct, then it either takes the constant running of a high intensity light to support the plants that are filtering the nitrates, or a dehumidifier to compensate for the pushing of oxygen rich air through a trick-down filter system.

I suppose, if you had a closed air system like mine..if it was feasable to redirect the exhaust air outside, then that would negate the need of running the dehumidifier. That would still effect the cost of running a furnace or AC though... ultimately not as cheap as the cost of doing water changes instead.

If someone claims the difference is solely the media.. I'll politely remain skeptical. I'll acknowledge the differences between bio media effectiveness, but not that one will do something completely different in the same setup as media of a different type. What? Are the japanese doing some sort of molecular engineering on their media that is specifially conducive to some different sort of new type of bacteria? If not, then it has to be a matter of simply maximizing efficiency of current filters. In fact, I wouldn't doubt, that if you had a sensitive enough of a nitrate testing kit, you can probably find that all filters actually help remove trace amounts of nitrates if they're working right.

they claim you need the expensive media from japan...........

[spiff]

Of course they do.

[johnptc]

Of course they do.

see http://www.makc.com/bakki.pdf


anmd http://www.absolute-koi.com/filtration/bakki.html

[spiff]

So it is just ceramic tube media with extreme water and air flow.... That means all of our regular bio filters are effecting nitrates too, just not enough to matter.

I'll test my filter then, as its very similiar to this, except using scrubbies and pillow stuffing instead of their "special" media. Similarities include: no accumulating water between drop and sump, multilple chambers, massive water flow. I'm all giddie now about testing this tonight. I'll wager that mine is probably making a dent to the nitrates then too, and could be increased if I wanted to open it to the air more..

[RoadWarrior]

Hey guys. Good thread! I hadn't checked up on it for a few days. Some comments about the posts since:

- My credentials: I have no credentials other than being someone who's kept fish off and on for more than 30 years, and who's spent a lot of time recently trying to study and evaluate what the various hobbyists are doing with filtration.

- People keep talking about space concerns, and admittedly, this set-up would require substantial space. It's the kind of set-up that would require a separate area behind closed doors, as you wouldn't want this filter out in the middle of a room. Bakki showers are somewhat noisy (like a small waterfall), and of course, if you incorporated the refugium sump with a reed bed, you're talking about an eyesore, as well as light issues. However, as I said in an earlier post, the Bakki Shower alone, without the reed bed and anaerobic sand bed, is still a very powerful filtration system.

- I still believe, however, that there's a real misconception out there about the size and cost of Bakki Showers. People see the ones that are produced for the commercial koi farming industry, and admittedly, those are very large and very expensive, as they're manufactured out of stainless steel. However, as a DIY project, Bakki Showers are extremely inexpensive. I've seen designs using milk crates, rectangular flower boxes, etc. It's the expensive media that drives up the cost.

I believe that you can make a Bakki Shower using bioballs. As far as the one poster's issues with media like Biohome and Bacteria House, that's the first time I've read anything regarding claims of bacterial die-offs within the capillary structure of the media. Having not used these products personally, I can only state that I've seen a lot of people on the koi forums who swear by them.

Obviously, the key with filtration media is surface area for bacteria colonization. Do these media have more surface area than any other media currently available? They certainly claim to.

Additionally, the manufacturers' claims that those media harbor bacteria that break down nitrates is one that people on the koi forums are attesting to, so the claim appears to be legitimate. I've never read any detractors on those forums who are actually using the products themselves.

- As for the combination of the components I included to address the removal of nitrates, I concede that there were redundancies there, as I incorporated three separate means to reduce nitrates. Bakki Showers do allegedly render nitrates almost undetectable if used appropriately, so you could argue that the other filter components in my design are redundant.

- As for the capacity to remove nitrates altogether using my filter set-up on a big tank with a heavy bioload (7 lbs. per day of food was cited), I would just say that the bioload of a tank like that would be comparable to the bioloads of koi ponds in which Bakki Filters are doing an outstanding job of removing nitrates almost completely.


I was very clear in my original post in stating that I don't claim to have all the answers. The design was one that to me represented the best possible low-tech solution for effective and thorough water purification in an aquarium or pond. It was nothing more than a draft intended to promote discussion.

The intent of my post was not to sell everyone here on my ideas, but rather to get a productive discussion going about the state of the art in home aquarium filtration technology, so that we could have a good exchange of ideas. We can all benefit from discussions like that.

[johnptc]

great thread topic thanks for posting.........

[cvermeulen]

Well... I have some thoughts on the Nitrates discussion... which seems to be the major cause for question, other than the space constraint.

1) A Bakki shower is nothing but a bio tower with a lot of aeration, UNLESS you count the use of the japanese media... in which case the japanese media should work just as well in a regular wet/dry, right? The only difference in a regular wet dry would be less aeration.

2) Denitrification, according to pretty much everything I've read, needs to take place in an anoxic (or anaerobic) environment. The japanese media claims to accomplish this with capilliaries, but the massive aeration of the bakki tower structure would work against this idea... so I'm not entirely sure why you wouldn't do a regular submerged biofilter with the "super media" and then run a shower or drip plate to re-aerate the water and de-gas the byproducts of denitrification.

3) Clogging the media: a valid concern. Mechanical pollutants, dead bacteria, algae, and just general crud is going to fill up those capilliaries sooner or later. I guess a good question is where do the nitrates GO? you make nitrogen gas, and a bunch of other stuff. That 'stuff' is either going to be a soluable pollutant (DOC-bad), or a precipitate (better). If it's a precipitate, it will also clog your media. Or, it off-gasses as SO2, CO2, and N2 (best) but still leaves the misc DOC's in your water to accumulate over time so you need periodic water changes (or another stage of filtration) to deal with them.

4) Where do the denitrifying bacteria get their source of edible carbon, or sulfur? (from what I understand, the various forms of denitrifying bacteria need one or the other to combine the left-over oxygen with to produce Sulfur dioxide or Carbon Dioxide). If the media already has one or both of these, the media will deplete over time.

I think that for dealing with nitrates, you can't get around the use of plants, or else a disgustingly large amount of bio-media so that it won't rapidly clog or deplete, and there will be enough water flow through the anoxic areas to actually deal with nitrates at an effective rate. Check out JohnPTC's Anoxic Carbon recombinant denitrifier for a good example. He's used over 1000 gallons of bio media to denitrify a 10,000 gallon tank, which I guess is not an unreasonable scale (10% of tank volume). HE has built a dedicated filter though with an appropriate flow rate for anoxic processes - accomplishing the same thing in a highly aerated wet/dry or bakki setup would require a ridiculous amount of media.

[johnptc]

http://www.monsterfishkeepers.com/fo...t=bakki+shower


also of interest

[spiff]

It makes me wonder how useful an airstone might be in a sump if you didn't already have an aerated system dumping into it...