Alternative Nitrate Reduction Method$

[Bruce Leyland-Jones]

All of this looks really good, but I have a horrible and persistently nagging feeling that some plant roots might be toxic.

 

[FishHobby99]

I have the same horrible and persistent nagging feeling that some plant roots might be toxic if we use concentrated acid to extract poisonous molecules. Don’t try this at home and don’t dip any important appendages into the water, lest they dissolve.

 

[FF_Member146894]

it might not be harmful to fish if they nibble on it a little bit, but if i was to add pothos to a certain one of my (plant-eating) puffer fish tanks, and if they ate all of the roots in one go, it would probably be harmful, right?

 

[FishHobby99]

Could well be! Possibly hazardous to your health if you devoured the whole cow in one fell swoop.

 

[dasaltemelosguy]

I can offer a little information on this topic. In truth, almost all Epipremnum and riparian plants have that 'toxin' throughout the entire plant, Calcium Oxalate (although the greatest % is in the leaves). It actually is not toxic per se but rather, it forms caustic crystals that can damage some creatures tissues who attempt to eat it.

Calcium Oxalate remains solid in a solution where the PH is 4.5 or higher. It cannot dissolve in higher PH's such that it never goes into solution in a normal aquarium.

In fact, you can test this yourself inexpensively with most home urinalysis test strips. The "Calcium Test" on most of these test for Oxalic Acid as well as Calcium content. Calcium Oxalate can only exist in water if Oxalic Acid is present, as the latter indicates the Calcium Oxalate has begun to dissolve:

Test for Calcium Oxalate

As the above is calibrated in mmol's, it needs conversion to PPM but we don't actually need an absolute value as we're only seeking to know if any Calcium Oxalate has leeched into the water, so all you really need is a relative value. Test the water before and after the addition of the pothos after 2-3 weeks and see if any Calcium Oxalate is present. After a year, I still read 0 change on this.

Still, I feel the best approach with these plants is to do as Jenny Solano did and wash the roots vs cutting them. Even if leaching were possible, (and you can test for this as above) the probability would be much greater with cuttings than roots. That adds additional protection against leeching. But again, this cannot occur above PH=4.5.

This is entirely anecdotal but these guys (the Severums that is, the Acaras don't care!) have been eating pothos roots for over a year and all I've seen is the pothos grows a little more slowly than in my other tanks:

 

[FishHobby99]

I can offer a little information on this topic. In truth, almost all Epipremnum and riparian plants have that 'toxin' throughout the entire plant, Calcium Oxalate (although the greatest % is in the leaves). It actually is not toxic per se but rather, it forms caustic crystals that can damage some creatures tissues who attempt to eat it.

Calcium Oxalate remains solid in a solution where the PH is 4.5 or higher. It cannot dissolve in higher PH's such that it never goes into solution in a normal aquarium.

In fact, you can test this yourself inexpensively with most home urinalysis test strips. The "Calcium Test" on most of these test for Oxalic Acid as well as Calcium content. Calcium Oxalate can only exist in water if Oxalic Acid is present, as the latter indicates the Calcium Oxalate has begun to dissolve:

Test for Calcium Oxalate

As the above is calibrated in mmol's, it needs conversion to PPM but we don't actually need an absolute value as we're only seeking to know if any Calcium Oxalate has leeched into the water, so all you really need is a relative value. Test the water before and after the addition of the pothos after 2-3 weeks and see if any Calcium Oxalate is present. After a year, I still read 0 change on this.

Still, I feel the best approach with these plants is to do as Jenny Solano did and wash the roots vs cutting them. Even if leaching were possible, (and you can test for this as above) the probability would be much greater with cuttings than roots. That adds additional protection against leeching. But again, this cannot occur above PH=4.5.

This is entirely anecdotal but these guys (the Severums that is, the Acaras don't care!) have been eating pothos roots for over a year and all I've seen is the pothos grows a little more slowly than in my other tanks:

View attachment 146417

Interesting the Severums nibble. My goldfish ignore the pothos roots & these guys have made quick work of many aquatic plants.

 

[StevenF]

They evolved with leaves under the sun, and in turn, enjoy more light energy which allows them to directly process nitrates more efficiently. Aquatic plants first absorb ammonia and will attempt to expend more energy if need be photosynthetically to consume nitrates so long as enough light energy is present.

This section is not entirely correct. all plant Aquatic and non-aquatic will consume ammonia, urea (CO(NH2)2, and nitrate. They only difference is that it takes little to no energy for plants to use ammonia or urea but using nitrate does require expending a little more energy to extract it. Anubis and many plants used in aquarium are actually terrestrial plants.

One example being a massive 900gph canister filter with some 6L of media capacity and TWO of these filters with a total of 12L of media, still cannot support enough media for effective anaerobic colonies for a ‘typically stocked 125G cichlid tank’ for significant nitrate reduction.

There is a very good reason why these big filters failed . Too Much oxygen. to insure we have enough oxygen in the water for fish we want good surface water flow. However for nitrate consuming bacteria you want low oxygen conditions. And probably the bet way to achieve that is low water flow (less than 1GPM) through a sand bead filter. When the oxygenated water from the tank enters the filter conventional bacteria will use the available oxygen to consume the organics in the water. As they do so oxygen levels will fall and CO2 level will increase. So for each in of travel through the filter oxygen levels will drop. Eventually all most all of the oxygen and has been replaced with CO2. At that point in the filter nitrate bacteria start consuming the nitrate because it is the only available source of oxygen left to break down organics. The bacteria will continue to consume nitrates and organics as long as oxygen levels remain low.

Unfortunately it might not be possible for such a low flow filter to keep up with nitrate production in the tank. With such low water flow it may take days to fully process all the water in the tank.

Note I never actually built such a filter because I simply went straight to plants and my tank was never heavily stocked. Also It should be pointed out that in heavily stocked tanks the fish waste will provide all of the 14 nutrients plants need to grow. As long as the plants are growing they will consume nitrogen. however in a lightly stocked tank there may not be enough nutrients in the water for the plants. The plant growth will then stop or the plant dies. When that happens nitrogen consumption stops.

 

[dasaltemelosguy]

I agree with what you've stated and you made me realize I misspoke on the filtration. I euphemistically referred to the "two massive 900GPH canister filters" as an indication of their massive size (each holds 25 gallons!).

I didn't realize in my clumsily phrased statement, that it implies they were flowing at 900GPh which was far from the case. I apologize for the confusion.

The two canisters used for the anaerobic cultivation were rheostatic-ally flow limited for the first month as they measured what flow rate had the greatest efficacy of anaerobic colony growth and separately for nitrate consumption. I believe they settled on a rate of 25gph for maximum efficacy of cultivating the anaerobic colonies in these two huge pond canisters.

As they are an LFS, they wanted to use commercially available media as opposed to something customized. They used BioHome Ultimate in one canister and Seachem Pond Matrix in the second. These two media supposedly have an internal architecture that favors anaerobic cultivation. Pond Matrix is a natural stone but larger and chosen for favored porosity and BioHome is a manufactured media designed to have favorable conditions for anaerobic colony cultivation.

Despite optimal conditions, the 'Catch 22' if you will is exactly as you stated previously. The flow needs to be reduced for anaerobic cultivation but reducing the flow reduces the nitrate consumption!

To that end, we were never able, by the end of the Y1 test period, to see nitrates reduced by more than 10PPM with 25L of media!

I agree also on the plants but I can add a little to it.

If a plant reduces ammonia to ammonium or uses nitrates directly, is of course species-based but largely, it's wavelength based.

Terrestrial plants will typically see more red and white light whereas submerged plants not only see subdued white light (relatively), they see a spectral change towards blue which will exhibit much less photosynthetic energy than red such that the plant may not have the available energy to directly consume nitrates and will instead convert ammonia to ammonium.

As you said, the ammonia/ammonium conversion requires much less energy which is but one reason aquatic plants tend to favor ammonia vs nitrates. This further compounded by the fact that ammonium is a cation and nitrate is an anion so ammonia is more readily processed by this metric as well.

The environmental reason however is largely spectral. The wavelengths that power nitrate consumption reach peak efficacy at about 660nm, Red, or optimal efficacy for chlorophyll and phytochromes (below is such an example but it focuses on green light absorption).

Blue light too can power nitrate consumption but it is subdued by water penetration AND in that in concert with the shorter wavelengths and the ionic charges, it is much less efficient in processing nitrates as they require more energy for reduction as opposed to the simple conversion of ammonia to ammonium as aquatic plants do.

All told, it's a lot easier for most of us to remove nitrates with plants than filters!

 

[Sgooosh]

All of this looks really good, but I have a horrible and persistently nagging feeling that some plant roots might be toxic.

and some plant roots are yummy to snails, my mystery snail wrecked a plant i was trying to grow


there is one very very dangerous, risky, but effective and save method........ duckweed...
grows fast and soaks all your nitrates like a sponge, then you can compost it or let fish eat it

 

[FishHobby99]

I had the good fortune of limited access to an ichthyologist and marine biologist who operate an LFS here in Southern California and work at an aquarium in San Diego. We began what became almost a full year of informal but largely quantified gatherings of data on nitrate reduction techniques and efficacy. Some is unfortunately anecdotal but much of it was quantified in a way that some Aquarists may find helpful.

Filtration options for nitrate reduction, can be difficult, expensive and surprisingly fragile. The aerobic bacteria consume ammonia and nitrite, the anaerobic consume nitrates...but the latter are fussy eaters! Nitrate reduction via filtration often has little to no effect as it can take 6-8 months to build a sufficient anaerobic colony to actually reduce nitrates meaningfully...and this requires enormous volumes of media.

Far more than would be need for the rest of the nitrogen cycle!

We began cultivating anaerobic colonies in pond media and found the amount of media required for an efficacious anaerobic colony to be far greater than we hoped for or that would be practical. Nitrate reduction via anaerobic colony filtration is VERY inefficient and requires voluminous amounts of media for meaningful nitrate reduction.

One example being a massive 900gph canister filter with some 6L of media capacity and TWO of these filters with a total of 12L of media, still cannot support enough media for effective anaerobic colonies for a ‘typically stocked 125G cichlid tank’ for significant nitrate reduction.

One such filter has ample amounts of flow and media capacity for aerobic colonies (the bacteria that removes ammonia and nitrite), but for anaerobic colonies (the bacteria that consumes nitrates), you’d need FOUR such canisters (25L pond media or similar) to have enough media to reduce nitrates just 10PPM!

I also find anaerobic colonies are MUCH more fragile than aerobic such that they are easily killed by accident. I cannot quantify this but I have experienced the results and I’ve yet to successfully neutralize rechargable media well enough to NOT reduce the anaerobic colony count.

In fact, re-using rechargable (with bleach) media that was then soaked in dechlorinator for 24 hours still killed off almost 6 out of 8 months growth of the anaerobic colony! Yet the aerobic bacteria saw no drop in population.

(I believe Pond Guru mentions a similar test and results in some of his videos)

I went a different route after months of trying to get meaningful nitrate reduction in the filters. Instead of trying to get nitrate reduction with more filters or additional media, I tried Epipremnum/riparian plants: roots in the water, leaves out the top.

I replaced part of the glass with plastic lighting grid to support the roots and stalks:

View attachment 146215

View attachment 146216

I had initially added Epipremnum/riparian plants primarily because I thought it was pretty. I had NO idea the degree of nitrate reduction this would have. I was not prepared for the results.

One tank was a 120G heavily stocked with adult, SA cichlids, 12 Acaras, 2 large plecos and 8 Severums in this case:

View attachment 146220

A 2nd tank, a 125G was heavily stocked with larger fishes, plecos, Oscars and pacu’s (I’ve since had to rehome my beloved pacu’s as they were approaching 18″ in length!):

View attachment 146221

The following are before and after a two week period with Epipremnum/riparian plants above in these tanks:

-The 120 typically reached circa 40ppm after a week when I’d do a WC.

-Inside of two weeks, the 120G at 40ppm has yet to ever reach 10ppm.


-The 125 was more problematic with nitrates I was having enormous difficulty controlling. This tank (prior to rehoming the pacu’s) would typically reach 80ppm-160ppm inside of 1 week (!) such that I was performing 2-3 WC’s/week until I could rehome them!

-Same time frame, the circa 80ppm-160ppm tank had still not risen to even 30ppm!

There was also little question that the nitrates fell further still once we installed grow lights. This is not shown in the pictures as they were not installed yet;

-With the lights on 12-16 hours/day or so, the 120 dropped from 10ppm to 5ppm, or possibly 0, it’s that difficult to read.

-The 125 dropped to 10ppm and has yet to ever reach 20ppm since adding the grow lights.

There are two properties to be mindful of in play and it’s entirely photosynthetic. Terrestrial plants use more nitrates vs ammonia than aquatic plants due to the availability of greater photosynthetic energy. They evolved with leaves under the sun, and in turn, enjoy more light energy which allows them to directly process nitrates more efficiently. Aquatic plants first absorb ammonia and will attempt to expend more energy if need be photosynthetically to consume nitrates so long as enough light energy is present.

The latter is more efficacious when the lighting is stronger which is not optimal for most aquatic plants nor the fish as the efficacy of nitrate consumption is quite related to the amount of light the plants are exposed to. Naturally submerged plants would see diminished light and evolve accordingly. But terrestrial plants evolved for this environment.

I used pothos and monstera in my tanks as well as Lucky Bamboo in a 3rd tank. A single, $20 pothos plant has virtually eliminated nitrates in the 120 and the same with the 125 since rehoming the pacu’s:

View attachment 146222

The big (literally and numerically) surprise was the dracaena or Lucky Bamboo. The pothos reveled its full potential in under 2 weeks. Lucky Bamboo took longer to display results, about 4 weeks vs only 2 weeks for pothos, but the 'bamboo' in particular has reduced nitrates so greatly, I’m not confident I can measure any at all with a liquid test kit now:

View attachment 146223

In my disbelief, I went out and bought a fresh liquid test kit to see if mine had spoiled but again, NO nitrates! A fully stocked SA cichlid tank with 0 nitrates? It sounded crazy to me but of all of the plants I’ve tried, Lucky Bamboo is the nitrate eating champion thus far.

What the image does not show is their growth. In case you were wondering where all those nitrates went, the Lucky Bamboo has grown from 24" stalks to now 6' in height!

View attachment 146224

One topic that will no doubt be raised and rightfully so, is the toxicity of certain plants and their utility in an aquarium. In particular, pothos is known to be toxic to some animals.

But in truth, nearly ALL Epipremnum/riparian plants, even monstera have this same toxin throughout the entire plants, leaves and roots. The toxin is Calcium Oxalate. It's not actually toxic to fish due to it's insolubility as it requires a very acidic environment to leach into the water as it becomes soluble at PH = 4.5. Above 4.5 it's remains crystalline which is the actual issue for dogs and cats as the crystals can cause irritation or sores in mammals.

But even if it contains any toxins, if your PH is above 4.5, it cannot leach into the water as it's insoluble.

Admittedly we performed no tests on this as the LFS owners have actually not seen an incident of toxicity with Epipremnum/riparian plants in any of their aquariums nor their customers. In truth, even if it were toxic, the leaching ability can only occur when the plant is cut AND the PH is below 4.5.

I don't bother with rooting cuttings. I just wash the roots and let them drape into the tank through the plastic lighting grid. Of all my fishes, only the Severums eat the roots (and the plecos eat the algae on the roots). I have seen my Severums eat the roots for years without incident:

View attachment 146225

While it may not appeal to everyone, a single Epipremnum/riparian plant can remove virtually all the nitrates directly from the water column if given enough time (weeks). I wish this could be more extensive and exhaustive but given the limitations of our testing, one thing I can say with confidence is there's no greater nitrate reduction one can get for a freshwater tank for $20!

Hi, I added a decent sized pothos, a smallish monstera and 4 tall Lucky Bamboos to my cichlid tank. As I recall, you observed nitrate reduction from pothos 2 weeks and 4 with the “bamboo.”

Is uptake time dependent solely upon root volume? I have yet to see results. It’s been maybe 3 weeks. Would more roots increase uptake, or are other variables involved?

 

[StevenF]

Is uptake time dependent solely upon root volume? I have yet to see results. It’s been maybe 3 weeks. Would more roots increase uptake, or are other variables involved?

The primary variable is nutrients and growth. Plants will not consume nitrogen if they cannot grow. Plants use nitrogen to make DNA and other compounds involved in growth. If the plant is not growing or growing slowly nitrogen consumption will be minimal to low. Other than nitrogen 13 other elements are needed for growth. If you just run out of one growth will stop and the other nutrients such as nitrogen can build up.

If it has been 3 weeks and you have nnitrate levels are not seeing results you plants likely ran out of nutrients other than Nitrogen. Of corse you do need enough light for the plant to grow rapidly enough to consume the nitrogen. But that said Pothos does do well in low light so I doubt your lighting is insufficient. So it is Probably a micro nutrient deficiency, or not enough calcium or magnesium in the water. You may have to fertilize the water to reduce your nitrates. The best micro nutrient fertilizer I know of is this one.

 

[FishHobby99]

Thanks kindly for your informative reply. The lighting should be sufficient. I suspended a grow lamp over the tank as it‘s on the dark side of the room. Someone gave me a bushel of chemicals that includes Seachem’s Flourish. I only used it once, given an aversion to adding anything to the tanks. I need to get past thIs ASAP as my terrestial & aquatic plant inventory is rapidly expanding.

 

[dasaltemelosguy]

That looks beautiful! This is anecdotal but for example, in my 75G, I have 10, 2' stalks (originally, now 6'), an anthurium and an entire pothos plant. Each time I added one, it drooped for 2-3 weeks before coming out of 'shock' if you will. I didn't see any nitrate use until I saw the first new growth. Then it really takes off. As they grow, nitrates slowly drop until as said above, you don't have enough to maintain growth. I didn't see 0 nitrates in that tank until month-8. All I saw at that point was slower growth.

Although a good idea, I wouldn't worry about adding nutrients right now based on what happened here as your plants are still small and they will grow a great deal over the next few months. I wish I could find it but there's a 55G with pothos on reddit with 25' vines!

 

[StevenF]

i

That looks beautiful! This is anecdotal but for example, in my 75G, I have 10, 2' stalks (originally, now 6'), an anthurium and an entire pothos plant. Each time I added one, it drooped for 2-3 weeks before coming out of 'shock' if you will.

Just a note Pothos plats are the of the same family as Anubis. I did put my one in my tank experimentally some time ago. It didn't suffer any shock at all and immediently started to grow. But at that time I was making my own fertilizer and was confident that i had all nutrients available in my tank. Based on my experience most of the shock people report seeing in aquatic plants is do too the plant adjusting from getting all its utreints from nutrient rich soil to much lower nutrients levels in aquariums.

Someone gave me a bushel of chemicals that includes Seachem’s Flourish. I only used it once, given an aversion to adding anything to the tanks. I need to get past thIs ASAP as my terrestial & aquatic plant inventory is rapidly

I would recommend not using Flourish. it is basically deficient in copper, zinc, and Molybdenum and didn't work in my RO water tank. I basically confirmed that in my own tan by making my own fertilizer using the same ingredients that are used in Flourish. I basically had to use about 20 times the amount of copper and about 30 time the amount of zinc that was in the bottle. And I had to dose Molybdenum separately because I found it was not compatible with the other ingredients. What I am using now is very similar to what is in the GLA product I recommend. The ingredients GLA uses are not toxic at the recommended dry dose of 1/64 tsp per 10 gallons. But if you are still concerned I am using a dose about 1/5 of what GLA recommends in my 5 gallon shrimp tank.

 

[FishHobby99]

That looks beautiful! This is anecdotal but for example, in my 75G, I have 10, 2' stalks (originally, now 6'), an anthurium and an entire pothos plant. Each time I added one, it drooped for 2-3 weeks before coming out of 'shock' if you will. I didn't see any nitrate use until I saw the first new growth. Then it really takes off. As they grow, nitrates slowly drop until as said above, you don't have enough to maintain growth. I didn't see 0 nitrates in that tank until month-8. All I saw at that point was slower growth.

Although a good idea, I wouldn't worry about adding nutrients right now based on what happened here as your plants are still small and they will grow a great deal over the next few months. I wish I could find it but there's a 55G with pothos on reddit with 25' vines!

By “first new growth“ do you mean leaves or roots?