The myths and legends of anaerobic bacteria

[anewbie]

On 6/17/2021 at 2:09 PM, MJV Aquatics said:

It is only anoxic or anaerobic bacteria that can convert nitrates into nitrogen gas and these conditions are difficult to achieve and maintain in the highly oxygenated fresh water aquarium. I've tried for a very long time with deep sand, Seachem Matrix/De*Nitrate filters with low flow, and Dr. Kevin Novak's Anoxic Biocenosis Clarification Baskets and just never see significant nitrate reduction. The very best approach seems to be with fast growing floating plants and routine partial water changes. 🙂

Routine periodic partial water changes, like rain and/or snow melt do imitate nature as polluted water is replaced by fresh, clean water. In the very best system, fresh water would be constantly added as used water drains away.

Well i had a heavily over stocked tank (20 long) with 3 inch very fine substrate that had the nitrate remain around 2ppm for about 6  months. So we can speculate why the nitrate level was so low but i'd put my coins on bacteria. The test i ran was quite valid as i have multiple tanks and test them in parallel and consistency this was the only tank that had ultra low nitrate.

[Guppysnail]

Not an expert or scientist but I tried something.  I read serval research papers. Tests were sand and gravel. 2in 4in 6inch deep in each on one I don’t remember the depths for the others. Or all the specifics. Each was filled with water...here is a debate because each was filled to the same level on the container on this one the others used identical liquid measures meaning each received different oxygenation based on surface area to volume of water.  Each received the exact same commercial fish food measures in kilograms on the one I remember.  nitrite and nitrate levels were tracked weekly over 1 year. As expected the initial 2 phases of the nitrogen cycle were skewed in this due to concentration levels of food in less water.  The others performed equal.

now to nitrate....it took 4 months to notice a slightly lowered nitrate amount 6 months for significant and I believe it was 8? Months for reliable. The deepest gravel outperformed the deepest sand which was unexpected by the papers author and performance decreased with decrease in substrate. 

I got excited I used one of my tanks with gravel. I had a ridiculous looking 4” sloping to 6” in gravel substrate 10 gallon tank.  (CPD’s didn’t care)What I failed to realize was the speed the nitrates rose over time increased drastically.  I was testing each morning and still performing water changes to keep it safe. By the time I realized not disturbing the substrate as was the caveat in a tank with no root feeding plants ..at first normal by the end when I gave up I would be at 20-35 after water change...my tap norm of 10. by the next morning I was at 80.

all the accumulation builds and really did become a nitrate factory. All the experiments I read included no living creatures.  I would not subject my pets to such high nitrates even intermittently so I gutted the substrate. 

If someone were ambitious and set up a tank and fed it religiously like these studies with no life in it to harm until it established it could be successful in my crazy old lady opinion.  

[HH Morant]

Guppysnail, that much substrate in a 10-gallon tank means significantly less water. The same amount of food and less water means higher nitrates. I think your results would need to be adjusted for that.

[Guppysnail]

On 6/17/2021 at 7:16 PM, HH Morant said:

Guppysnail, that much substrate in a 10-gallon tank means significantly less water. The same amount of food and less water means higher nitrates. I think your results would need to be adjusted for that.

Yeah...not a real experiment just a curious old lady past time but the articles were very fascinating 

[MJV Aquatics]

On 3/31/2021 at 9:00 AM, gardenman said:

Even the heaviest of rainfall is less than a fifty percent water change we often carry out in our tanks. Doubling the volume of the Amazon would take a heck of a lot of rain.

The water change of the Amazon river is not the result of a single rain storm over water but a constant never ending flow of fresh water.

Edited June 18, 2021 by MJV Aquatics

[gardenman]

I've been thinking of making a three chamber HOB that would have a top down mechanical filter (layers of filter material that could be stacked then peeled off as they become soiled revealing fresh material under them.) A biofiltration chamber that would likely be  fluidized K1 or a similar material and then a largely isolated chamber off to the side that would be filled top to bottom with gravel/sand. The only water flow to that would be smaller diameter holes in the bottom, and then a pothos, impatiens or some other water tolerant terrestrial plant planted in that chamber. The HOB would extend above the top of the tank by a good bit. Water would flow in from a pump in the tank into the mechanical filtration area. Since most of the bonded filter material readily available is 12" wide, I'd make that chamber twelve inches wide. That would make cutting the filter material to size much easier. Maybe make it three inches front to back and maybe sixteen to eighteen inches deep. 

I'd pretty much steal the design of the various sealed fluidized filters for the fluidized chamber and make it easy to toss an airstone into the bottom to fluidize the K1. Then the third chamber would largely just sit there and house the plant with no real water flow through it. I'm assuming as the plant consumed the nitrates new nitrates would move from the tank water to the plant water. The chamber itself would be largely anoxic and relatively harmless to the fish since it would be external. Any harmful gas built up wouldn't enter the tank. Combining an external anoxic chamber with a nitrate consuming plant would seemingly give you the best chance of seriously depleting nitrates.

In theory, water would flow into the mechanical filtration area, downwards through the filter material across into the biofiltration fluidized chamber, then up and overflow out into the tank. (Which is why the filter would protrude above the tank. I'd count on gravity returning the water to the tank.) The deep (maybe 14") gravel/sand bed in the adjacent chamber would have essentially no flow through it. It would just sit there holding the pothos or whatever plant and suck up whatever nitrates found its way there. I kind of figure three inches square by about 14" deep for that chamber.

To build it I'd use acrylic. Make a box first that was say three inches front to back and 18 inches side to side. (one 12" chamber and two 3" ones. (A bit less than 3" due to the thickness of the acrylic.) The box would be pretty deep, say 16"-18". Lots of room for filtration stuff. There would be a perforated grid in a half inch or so off the bottom all the way across. I might run a solid piece of airline tubing down to the bottom of the fluidized chamber with an air stone attached. Two vertical dividers creating the three chambers. Some sort of an upper grid on the fluidized chamber to keep the K1 from floating away. Then an outlet above the fluidized bed chamber for the water to flow back to the tank. It would require two pumps to work, an air pump and a water pump, but it should be a pretty efficient filter. In theory, it should solve lots of the issues people have with filters. It would be easy to clean the filter, simply peel off a soiled pad. Most of the bonded pads are about an inch or less thick. If the box is 16" deep with a half inch space on the bottom you could put as many as fourteen layers of pads in at a time and then not have to replace them until you've peeled away all fourteen. You don't even have to shut off the filter to clean it. Just roll up a dirty pad and there's a clean one under it. The then mechanically clean water goes into the biofiltration area where oxygen rich water keeps buffeting the K1 to keep it clean and functioning optimally. Then back to the tank. Meanwhile. Mr. Pothos is sitting there in a largely stagnant pool of water and sucking up nitrates while anoxic bacteria do their thing.

It all makes sense to me. Would it work? Pretty much any filter works. It's just a question of how well would it work. If I get bored over the summer and have some acrylic lying around I might just build it to see. What's the worst that could happen? I kind of expect the pothos or whatever plant to send roots down through the substrate and into the void beneath the other two chambers. Not that that's necessarily bad. Water wouldn't flow through the anoxic chamber other than what transpired through the pothos. It might actually work.

 

[gardenman]

On 6/17/2021 at 9:17 PM, MJV Aquatics said:

The water change of the Amazon river is not the result of a single rain storm over water but a constant never ending flow of fresh water.

The Amazon has a rainy season and a dry season. There's not always fresh water flowing in. From the end of February through July is the rainy season. Then there's lots of fresh water flowing in. After that, not so much. Is there some? Yes. But not a substantial amount during the dry season. The water level rises quite a bit during the rainy season then recedes a lot during the dry season. 

[MJV Aquatics]

On 6/17/2021 at 9:30 PM, gardenman said:

The Amazon has a rainy season and a dry season. There's not always fresh water flowing in. From the end of February through July is the rainy season. Then there's lots of fresh water flowing in. After that, not so much. Is there some? Yes. But not a substantial amount during the dry season. The water level rises quite a bit during the rainy season then recedes a lot during the dry season. 

Yes, but as far as I know, a substantial amount of fresh water flows constantly 24/7, year round so there is always fresh water flowing. 🙂

Ever been to Niagara Falls and marveled at the volume of [fresh] water that flows between the great lakes?

Nature constantly recycles and replaces/refreshes fresh water.

Edit: As a matter of fact, imitating nature, the best aquarium setup would be a flow through system where fresh water constantly replaces used tank water at some appropriate rate. This is often done in large breeding facilities or sometimes automated daily partial water changes. Unfortunately, short of a dedicated fishroom, this is just not practical for the home aquarium so we do routine partial water changes of a sufficient volume to maintain an acceptable water chemistry. I tend to do 50%+ weekly, but on heavily stocked grow out tanks, I often do 50% twice a week.  Although methods to lower, or eliminate nitrates are not without merit, nothing beats replacing polluted water with fresh, clean water. You've likely heard that "there's no such thing as too much filtration". Well that's a hobby myth, but in general, there's no such thing as too much clean, fresh water.

Edited June 18, 2021 by MJV Aquatics

[gjcarew]

On 6/17/2021 at 6:30 PM, gardenman said:

The Amazon has a rainy season and a dry season. There's not always fresh water flowing in. From the end of February through July is the rainy season. Then there's lots of fresh water flowing in. After that, not so much. Is there some? Yes. But not a substantial amount during the dry season. The water level rises quite a bit during the rainy season then recedes a lot during the dry season. 

There is literally constant freshwater flowing through the amazon. Like, millions of gallons per second, even during the dry season. That is the nature of rivers, regardless of the flow rate. They have near 100% turnover relative to a stationary object at every moment. The Amazon is also not only fed by rain but by snowmelt from the Andes, it never just dries up.

 

[Antonio]

Ive been using biohome ultimate in a fluval 407. 29 gallon breeder. Biohome ultimate is supposed to hold properties for denitrafication bacteria

Havent done any water changes in about 6 months as an experiment. It was setup for about 3ish months on a tank that had shrimp and rummynoses in it.

So I only check their noses daily and never tested the water. Shrimp seemed fine too breeding colony going strong. And so the past week I decided to buy center piece dwarf gourami.

Acclimated her and tossed her in. Woke up and she was dead. Confused I tested the water and its over 100 ppm nitrates. Rummynoses are still red and happy shrimp thriving. Im afraid to disturb the breeding colony.

It has some plants but far from heavily planted.

Adding frogbit back to it asap and gonna let dwarf 4 leaf clover take over. Waiting on the 4 leaf clover but wow those nitrate numbers should be draining my fishes lives......

100ppm nitrates, 0 ammonia, 0 nitrite

I only ran the 407 on half bc I was too lazy to drill extra holes on the spray bar. Drilled holes in it and cranked it to max.

Also havent ever cleaned my filter but again until chunks come flying out or until my shrimp/rummynoses arent doing well I aint changing it. Not  messing with the colony unless I see a batch of dead baby shrimp.

Im confused on the nitrates though... even my other biohome tank has insane nitrates but chili rasboras and betta are fully colored up and happy

Are these real nitrates I'm reading or is like nitrate-delta lol these fish should be colorless or dead by this point shouldnt they? Poor gourami was an accidental guinea pig. I just assumed biohome took care of the nitrates bc everything was peachy for months now... color me confused

 

[modified lung]

@Antonio they're real nitrates I'm sure. When it comes to things that aren't very toxic like nitrate, a fish might handle a slow build-up no problem, but not suddenly going from 0 to 100.

[dasaltemelosguy]

Hi @Antonio, unfortunately, he's correct, they're real. There's a Catch-22 with trying to reduce nitrates via any media.

Anaerobic denitrification or Anoxic Denitrification as the rigs designed for nitrate reduction are known, require slow flows to avoid oxygen build-up and allow a friendly, anoxic environment for anaerobic bacteria to grow. The media's architecture is designed for this purpose as well.

The slow flow of course defeats much of the purpose in that to enjoy enough flow to meaningfully reduce nitrates in the tank is too much flow for a large colony to develop. So, denitrification beds tend to be huge such that a slow flow and enough nitrate consumption may take place simultaneously. 

It is done and it does work but the efficacy of even the best media like BioHome or Seachem's Pond Matrix is too small to be of much value in conventional filters with normal flow.

A 1-year experiment to quantify this was performed with three scientists, two from the AQ of the Pacific who also operated an LFS near Los Angeles, but the test was not at all esoteric but rather, their intention was to employ commonly available products and means as their customers often inquired. 

Another unfortunate aspect of the anaerobes was their fragility. The slightest presence of a toxin that frankly would escape notice of the fishes would kill off months of anaerobic growth. Ultimately, we decided to not recommend attempts to reduce nitrates via conventional filtration and elected to endorse the use of emergent plants (Some species consume a shocking number of nitrates). 

The anoxic denitrification beds do work and given the internal architecture, BioHome is probably the best media for anaerobes, but to us it seemed not worth the rather elaborate and often huge rigs required for most people. 

This is the piece should you be interested, good luck: 

Alternative Nitrate Reduction via Emergents (aquariumcoop.com)

 

[Antonio]

Hello @modified lungand @dasaltemelosguy

Yes I figured it immediately needed attention in terms of lack of plants and was real nitrates. Added whole range of green stuff and did the deepest of dives in Anoxic plenums and BCBs.

 

Its extremely interesting how well hidden all the scientific filtration info and videos are hidden from the new fish keeper.

 

Doubt I'll ever not use a plenum and I took a look at my fluval 407 and think I found evidence of bypass at the lowest tray so maybe poor water flow over the biohome idk

 

I guess the only weird thing Ive done to the tank was add montemorilite clay for fun. 

 

Biohome is a beast filter media but yeah wish someone wouldve told me about plenums or BCBs. Just ordered a ton of laterite from Africa for future filtration projects. Cant set one up soon bc Im about to move and dont want to deal with disturbing a new plenum. Too much weight on the glass etc but Im gonna make BCBs

 

 

Edited June 13, 2022 by Antonio

[JessLynne7]

I’m working on this myself. I’m building a new tank.

im going to run an hob and sponge filter for my aerobic bacteria. I am also making a plenum to build anoxic bacteria.

of course I have plants a mix of fast and slow growers but mostly slow.

im building now and will keep everyone posted

[Antonio]

Added a plenum sunday. Kinda went big with it. Biohome ultimate from filter, under a 29 gal pennplax undergravel filter, flourite red layer directly on the UGF, 2 bags of ammazonia ver 2 9L, topped it all with cheap sand from chewy.  Its too early to tell but I replanted my carpeting plants, ordered 2 lilys with some stem plants, and ordered a nitrate tester. I think once the roots hit the flourite red I'll see explosive growth. The roots will make paths for water to travel through to reach the UGF. Tons of testing on this setup. May update if I remember to

 

I like the way I hid the soil plenum with the sand. It needs cleaned up a little more but I'll make it instagram ready when the plants come in lol took all day and only lost one rummynose. He was swimming upside down the next morning and died before I got home with epsom salt. Poor chap