Emergent planted tanks and Nitrates

Can I ask just out of interest why you are interested in using terestial plants as a source to remove nitrates from your tank water column?

As far as I know, though to be entirely honest I have not researched this much at all before, terestial plants does not remove very much nitrate from tank water columns

I have always used floating aquatic plants such as water lettuce and silva natans as wells as having heavily planted tanks as an excellent source to remove nitrate from my tanks as I had high nitrate straight (40+ ppm) from water mains taps so water changes did neglible changes to nitrate levels.

Though Byrons very interesting quotes from Diana Walstead about either roots or leaves intake was something I had not considered previously but very valid points to consider when choosing plants for you tank especially if you have high nitrates, a very intersting read nonetheless.

There are definately some product out there in various LFS that claims to remove nitrates, but tbh I do not have much faith in those as have always preferred the more natural ways to remove nitrate.

However I have considered in having a sump tank with lots of plants to remove nitrates when i thought about having cichlids only set up as I have very hard water and these fish species love to destroy or munch on plants hence that consideration.

Ch4rlie said:

I have always used floating aquatic plants such as water lettuce and silva natans as wells as having heavily planted tanks as an excellent source to remove nitrate from my tanks as I had high nitrate straight (40+ ppm) from water mains taps so water changes did neglible changes to nitrate levels.

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This is something that has come up a few times on TFF, and it is puzzling. Aquatic plants like the floating species you mention do not take up nitrate, assuming you are referring to a low-tech or natural planted tank. They take up ammonia/ammonium and only turn to nitrate if the ammonium is insufficient in balance with the other nutrient requirements and , obviously, light; light drives photosynthesis and without sufficient light intensity, the plants cannot photosynthesize (grow). Nitrate in the source water cannot be removed by aquatic aquarium plants--though in a high-tech method planted tank, this would occur because there the ammonia/ammonium will obviously be lower that the amount need to balance the high light and additional nutrients (like CO2 especially).

Byron said:

This is something that has come up a few times on TFF, and it is puzzling. Aquatic plants like the floating species you mention do not take up nitrate, assuming you are referring to a low-tech or natural planted tank. They take up ammonia/ammonium and only turn to nitrate if the ammonium is insufficient in balance with the other nutrient requirements and , obviously, light; light drives photosynthesis and without sufficient light intensity, the plants cannot photosynthesize (grow). Nitrate in the source water cannot be removed by aquatic aquarium plants--though in a high-tech method planted tank, this would occur because there the ammonia/ammonium will obviously be lower that the amount need to balance the high light and additional nutrients (like CO2 especially).

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That IS interesting actually. Puzzling indeed as I had assumed (perhaps assumed wrongly), that most fast growing floating aquatic plants were good for the consumption of nitrates in water columns.

Perhaps it was a combination of my other planted plants in those tanks that perhaps took up most of the nitrates in my tank water columns as by end of a normal week my nitrates would drop from 40-50ppm after the usual water change down to neglible levels, usually below 5ppm by the end of the week.

Though strictly speaking my tanks were not completely low tech set ups as I had good lighting but not so high that the plants would perhaps then require C02 sytem, large external filter for good water turnover and normally would add liquid ferts once weekly as well as good root tabs for the crytocoryne plants.

Also had no algae issues to speak of at all so algae would not be a primary factor in lowering nitrate levels in my case.

Am going to have re-evaluate and do more research on floating plants perhaps.

Interesting topic.

Ch4rlie said:

Can I ask just out of interest why you are interested in using terestial plants as a source to remove nitrates from your tank water column?

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Well, two reasons. First and most importantly, terrestrial plants would look really good with this setup. If they also keep nitrates low, bonus.

Ch4rlie said:

I had assumed (perhaps assumed wrongly), that most fast growing floating aquatic plants were good for the consumption of nitrates in water columns.

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For nitrates generated within the biological system of the aquarium, yes, this is true in a certain way. The plants take up the ammonia/ammonium, and they are faster at doing this than the nitrifying bacteria/archaea, so with significantly less ammonia for the oxidizing b/a, there is less nitrite, and thus less nitrate resulting. But this only works for nitrates being generated in the tank.

Hmm, so fast growing floating plants are best for biologically grown nitrates but not so much for nitrates coming from the main source such as tap water where levels can be 40+ppm

So in my case at least must have been down to the heavily planted tank that removed the majority of nitrate that occurred from water source, well that’s what logic tells me without having any other real evidence or proof otherwise.

Byron, thank you for that, a fascinating subject imho.

And apologies to WhistlingBadger for my hijacking his thread and veering from the subject slightly but very interesting.

Wow this thread is super interesting I was just browsing for emergent plant holders for tanks I know I've seen them before but couldnt think of which?

And it made me think of a trend that is happening in the planted tank world called Wabi-Kusa which people use plants we would know as aquatic plants in different ways - its mainly led by a brand called DOOA which is connected to Amanos ADA brand. But that got me thinking could we not use aquatic plants like Anubias or Cryptocoryens so their roots are in the aquarium water and their leaves are growing emergent? I know these two examples are slow growing but I wonder if there are any faster growing non stem plants that would work like this?

Wills

Wills said:

Wow this thread is super interesting I was just browsing for emergent plant holders for tanks I know I've seen them before but couldnt think of which?

And it made me think of a trend that is happening in the planted tank world called Wabi-Kusa which people use plants we would know as aquatic plants in different ways - its mainly led by a brand called DOOA which is connected to Amanos ADA brand. But that got me thinking could we not use aquatic plants like Anubias or Cryptocoryens so their roots are in the aquarium water and their leaves are growing emergent? I know these two examples are slow growing but I wonder if there are any faster growing non stem plants that would work like this?

Wills

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I've tried growing crypts and java fern emergent and I've never been able to get the stuff to come out of the water. I'm still hopeful that the Crypt pontederiifolia in my Sumatra tank will grow out of the water, blossom, and simulate taro at some point. Not yet. The only plants I've ever been able to grow emergent were paddy herb and water sprite.

Ch4rlie said:

And apologies to WhistlingBadger for my hijacking his thread and veering from the subject slightly but very interesting.

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No apology necessary! This is fascinating stuff.

WhistlingBadger said:

I've tried growing crypts and java fern emergent and I've never been able to get the stuff to come out of the water. I'm still hopeful that the Crypt pontederiifolia in my Sumatra tank will grow out of the water, blossom, and simulate taro at some point. Not yet. The only plants I've ever been able to grow emergent were paddy herb and water sprite.


No apology necessary! This is fascinating stuff.

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From what I know most crypts in particular come in emergent form as thats how they are grown in the greenhouses and why they usually 'melt' when they first go in the tank while they send out submerged form leaves which look different. Same with Sword plants actually which could be a good candidate for this kind of thing?

Are there any negatives to the Peace Lillies? They seem like a good option on face value?

Wills

Wills said:

could we not use aquatic plants like Anubias or Cryptocoryens so their roots are in the aquarium water and their leaves are growing emergent? I know these two examples are slow growing but I wonder if there are any faster growing non stem plants that would work like this?

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Quite a number of our "aquatic" aquarium plants are in fact not strictly speaking aquatic, but amphibious bog or marsh plants.

All species (there may be an exception or two, something tells me there is but I can't remember it) of Echinodorus for example, and Helanthium which now holds the "chain" sword species. Anubias you mentioned are the same, as is Java Fern. Some stem plants, like Pennywort, are the same.

Crypts are also amphibious, here's a section of my profile elsewhere:

Vallisneria are true aquatic plants, belonging to the Hydrocharitaceae family of floating and submersed aquatic plants, commonly called the Tape Grasses, which contains both marine and freshwater plants found on all continents in the tropical and temperate zones.

Ceratopteris species (Water Sprite) are true aquatic ferns.

If you want to grow Crypt's out of water build a shelf on the back of the tank like a brace made out of glass about 2 inches below the surface of the tank and then, put peat or what every you like on that covered in gravel and away you go. You can grow any plants you like along that shelf terrestrially
This is Crypt Nana growing that way, I'm waiting for it to flower.

In the past I have run full Hydroponic units above tanks the Lettuces would just remove all Nitrates from the tank. Healthy tank, lovely lettuces.

An LFS here in LA is run by two employees of the AQ of the Pacific, one a marine biologist and the other an ichthyologist. They have been kind enough to test samples for me, (usually a sick or dead fish) but recently we tested filtration media for nitrate reduction.

The issue being the bacteria that consumes ammonia and nitrites, the aerobic bacteria, colonize the filter media much more quickly than the type of bacteria that consume nitrates, the anaerobic bacteria. The latter forms much more deeply in the media material and is not subject nearly as much to flow and virtually no oxygen, hence they're anaerobic.

The folks at the AQP based this particular test on a 'real world tank' (as opposed to tanks where divers do the maintenance!), a 75G African Cichlid tank that is moderately overstocked for aggression.

The results were not surprising save for the amount of media required to reach the goal. In this example they used a 900gph canister with 6L of media. With 6L of media, once cycled, the tank is stable with a PH=8, 0, 0, 40ppm. They added a second canister with an additional 6L of pond media in an attempt to breed a large enough anaerobic colony to have a truly effective nitrate reduction.

In this example, they saw negligible nitrate reduction with 6L, about 5ppm with 12L and eventually they increased the media content to 25L which gave them a 10ppm average nitrate drop.

Ever mindful that this test took nearly a year!

The reason being, the anaerobic colonies don't mature for 6-8 months, so this is true in your filter as well. But you need a staggering amount of media to harbor sufficient anaerobic colonies to meaningfully reduce nitrates. Some 400% more than needed for all of the previous stages of the cycle.

As a side note, they found there was no degree of "neutralization of the bleach in rechargable media" that did not kill off some of the anaerobic colony. In fact, the anaerobic colonies seem to be quite fragile as eventually they abandoned using rechargable media completely as it cost them up to 6 months of anaerobic growth!

As Byron stated better than I can, terrestrial plants consume nitrates more readily than aquatic plants. The former evolved with greater light energy than submerged plants and in the photosynthetic process, it requires less energy to consume ammonia than nitrate, hence the terrestrials are nitrate sinks whereas aquatics are ammonia sinks (I'm speaking generically though).

A botanist friend pointed out that floating plants have more direct air exposure and with more CO2 available and less diminution of the light, tend to consume more nitrates as well. That same friend above corrected my nomenclature in that what I was about to share were my direct experiences with "riparian" plants in my tanks.

He told me what I actually am using is epipremnum plants. Roots in the water, leaves above. The fish love the roots, especially and not surprisingly, the severums. I used three types of such plants now and I can say with confidence that one in particular consumes nitrates at a rate that defies belief.



On my 3 tanks, one is a 125G, very overstocked with Oscars, plecos and Pacu's (soon to be rehomed) that grew far more quickly than I thought! The bioload is so great, I do 2 WC's/week and have 2 FX6's on it. Still, nitrates are 80ppm inside of a week.

I added a single $20 pothos plant as shown in the image. It took about 2 weeks but the nitrates plummeted from circa 80ppm to never higher than 20ppm. We added grow lights and it fell about 5ppm more.




On the 120G Acara/Severum/Plecos tank the bioload is less and I could see 40ppm if left unattended. With the same pothos and some monstera, it has yet to see even 10ppm.




The oddball (for me at least) is a 75G with adult EBA's, plecos. The bioload here is moderate and the worst nitrate reading I'd ever seen was about 40ppm. More typically, circa 20ppm. I added the Lucky Bamboo as seen below. This took far longer to be efficacious as the pothos enjoyed huge nitrate reduction in only 2 weeks whereas the LB easily took over a month to dramatically reduce the nitrates.

This is the one that surprised me the most though. After about a month, perhaps 6 weeks, I could no longer read any nitrates. I literally went out and bought a second liquid test kit as I thought my solutions had spoiled in some way.

After several months, I still cannot get a nitrate reading on the bamboo tank (I ritually perform my weekly WC's though). It's been PH8, 0, 0, 0 ever since. The bamboo itself I bought 10 stalks at 24" in height. They are now 4' tall! Oddly the stalks barely thickened, they just go....up!

(BTW Lucky Bamboo is not real bamboo...but it's pretty!)

With great license, the faster a plant grows, the more light it gets, the more exposure to the air, the more nitrate intake from most plants.

dasaltemelosguy said:

An LFS here in LA is run by two employees of the AQ of the Pacific, one a marine biologist and the other an ichthyologist. They have been kind enough to test samples for me, (usually a sick or dead fish) but recently we tested filtration media for nitrate reduction.

The issue being the bacteria that consumes ammonia and nitrites, the aerobic bacteria, colonize the filter media much more quickly than the type of bacteria that consume nitrates, the anaerobic bacteria. The latter forms much more deeply in the media material and is not subject nearly as much to flow and virtually no oxygen, hence they're anaerobic.

The folks at the AQP based this particular test on a 'real world tank' (as opposed to tanks where divers do the maintenance!), a 75G African Cichlid tank that is moderately overstocked for aggression.

The results were not surprising save for the amount of media required to reach the goal. In this example they used a 900gph canister with 6L of media. With 6L of media, once cycled, the tank is stable with a PH=8, 0, 0, 40ppm. They added a second canister with an additional 6L of pond media in an attempt to breed a large enough anaerobic colony to have a truly effective nitrate reduction.

In this example, they saw negligible nitrate reduction with 6L, about 5ppm with 12L and eventually they increased the media content to 25L which gave them a 10ppm average nitrate drop.

Ever mindful that this test took nearly a year!

The reason being, the anaerobic colonies don't mature for 6-8 months, so this is true in your filter as well. But you need a staggering amount of media to harbor sufficient anaerobic colonies to meaningfully reduce nitrates. Some 400% more than needed for all of the previous stages of the cycle.

As a side note, they found there was no degree of "neutralization of the bleach in rechargable media" that did not kill off some of the anaerobic colony. In fact, the anaerobic colonies seem to be quite fragile as eventually they abandoned using rechargable media completely as it cost them up to 6 months of anaerobic growth!

As Byron stated better than I can, terrestrial plants consume nitrates more readily than aquatic plants. The former evolved with greater light energy than submerged plants and in the photosynthetic process, it requires less energy to consume ammonia than nitrate, hence the terrestrials are nitrate sinks whereas aquatics are ammonia sinks (I'm speaking generically though).

A botanist friend pointed out that floating plants have more direct air exposure and with more CO2 available and less diminution of the light, tend to consume more nitrates as well. That same friend above corrected my nomenclature in that what I was about to share were my direct experiences with "riparian" plants in my tanks.

He told me what I actually am using is epipremnum plants. Roots in the water, leaves above. The fish love the roots, especially and not surprisingly, the severums. I used three types of such plants now and I can say with confidence that one in particular consumes nitrates at a rate that defies belief.



On my 3 tanks, one is a 125G, very overstocked with Oscars, plecos and Pacu's (soon to be rehomed) that grew far more quickly than I thought! The bioload is so great, I do 2 WC's/week and have 2 FX6's on it. Still, nitrates are 80ppm inside of a week.

I added a single $20 pothos plant as shown in the image. It took about 2 weeks but the nitrates plummeted from circa 80ppm to never higher than 20ppm. We added grow lights and it fell about 5ppm more.




On the 120G Acara/Severum/Plecos tank the bioload is less and I could see 40ppm if left unattended. With the same pothos and some monstera, it has yet to see even 10ppm.




The oddball (for me at least) is a 75G with adult EBA's, plecos. The bioload here is moderate and the worst nitrate reading I'd ever seen was about 40ppm. More typically, circa 20ppm. I added the Lucky Bamboo as seen below. This took far longer to be efficacious as the pothos enjoyed huge nitrate reduction in only 2 weeks whereas the LB easily took over a month to dramatically reduce the nitrates.

This is the one that surprised me the most though. After about a month, perhaps 6 weeks, I could no longer read any nitrates. I literally went out and bought a second liquid test kit as I thought my solutions had spoiled in some way.

After several months, I still cannot get a nitrate reading on the bamboo tank (I ritually perform my weekly WC's though). It's been PH8, 0, 0, 0 ever since. The bamboo itself I bought 10 stalks at 24" in height. They are now 4' tall! Oddly the stalks barely thickened, they just go....up!

(BTW Lucky Bamboo is not real bamboo...but it's pretty!)

With great license, the faster a plant grows, the more light it gets, the more exposure to the air, the more nitrate intake from most plants.

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That is really interesting! Thanks for sharing. Your tanks look great.

I wonder if the lucky bamboo, being a root feeder, sucked up all the nitrates from the substrate before it began taking it from the water. Possible explanation for what you experienced? I used to have some in a SE Asia tank and it is a really cool aquarium plant.

Beautiful tanks, @dasaltemelosguy !

@WhistlingBadger , I grow two emersed plants for nitrate removal:
- Cardinal plant (Lobelia cardinalis) gets beautiful red/purple foliage when closer to the light. Have them in a shallow tank (pea puffer) and also the Vampire crab paludarium which has tannins (black water).
- Peace lily (Spathiphyllum) in the shallow tank for the pea puffer.

I used to have pothos but decided to remove it since the critters peck at the roots when getting snails. These plants do an amazing job at Nitrate removal. I do not fertilize because one time I tried, algae took over, so it proved to me that the nutrient balance was there without fertilizers.

The added bonus is that they are easy to propagate. Here is the one in the paludarium: