Nitrates won’t go down

[Gage.R]

tank stats:

20g Long

light: Fluval 3.0 20% for 8 hours a day

ferts: liquid east green 2 pumps  once a week (although haven’t dosed since the issue. Easy root tabs 

plants: trident fern, tiger lotus, crypts, vallisneria, dwarf sag, dwarf Lilly, dwarf water lettuce.

c02: yes 

ph: 7.6pom

Ammonia:0ppm

Nitrite:0ppm

Nitrate: 40ppm

So I’ve been battling an issue with high nitrates in one of my my 20g longs with no livestock. I thought I knew the issues but I’m stumped on how to go about resolving it. This tank is “medium tech” with low amounts of c02 and low/light and liquid ferts, (with the exception of a lot of root tabs in the substrate). I do think that having a lot of plants that are heavy root feeders and slower growers is really up a big part of the issue here. The tank is  full of Vallisneria, dwarf sag, Crypts, a few tiger lotus bulbs, a dwarf Lilly bulb, swords, and a fair amount of epiphytes on the rocks and driftwood. (some dwarf water lettuce too). So because of this I have kept my water column fertilizing  schedule pretty minimal (2 pumps of easy green once a week). So the problem I ran into a few weeks ago is that my nitrates are consistently sitting around 40ppm. So because of this I’ve stopped my liquid ferts and increased  water changes.  When I first noticed this I did A 50% water change and rinsed out my filter sponge. I tested my water using both the API test kit and tetra test strips and still read about 40 ppm nitrates. So you may think that my tapwater could potentially be the issue however my tapwater has zero nitrates and about .50 ppm ammonia due to chloramines. So within the same week a few days later I did a 25% water change and a light hovering over the substrate as I cannot really “gravel vac” due to the large plant mass on the substrate. Next week I did another 50% water change and a 25% about three days later while hovering over the substrate and getting as much detritus as I possibly could. Once again after testing my tank, The nitrates were still 40ppm. Now this is without dosing liquid ferts, for the duration of doing these water changes over two weeks. Currently my nitrates are still reading 40ppm, so I did take a water sample to my trusted LFS and they got the same results so I am not convinced it is a test kit issue. What is making me question the efficacy of these test results is that my floating plants aren’t doing that great although the tank has a decently high flow so this could be it and the fluval 3.0 is positioned to the point of the light being very centered to the middle of the tank so portions of those floating plants aren’t getting as much lights  others. Now I am of the impression that this could possibly be that the ammonia in my tapwater is kind of canceling out the water changes in the sense of the ammonia just being converted straight to nitrates after removing nitrates. I’m at the point now where the dwarf lily starting to develop some small holes regardless of adding root tabs Weekly so I suspect this might want some liquid ferts as it is a huge plant now. I feel as if I know the answer already but failing to realize it.

Any help is appreciated.

happy holidays!

 

Edited December 24, 2021 by Gage.R

[Mmiller2001]

It's the root tabs leaching into the water column. Despite what people say, "heavy root feeders" do not need root tabs and do just fine with proper water column dosing. 

You will just have to wait out the leaching and do large water changes.

I would also crank up the CO2 and light, there's no reason to use CO2 and keep it low with those plants. 

Edited December 24, 2021 by Mmiller2001

[Gator]

@Gage.R; I read an interesting article online yesterday about Nitrates and plants that soak them up, Anubias is one and Pothos is another one, but you have to be careful with Pothos. It seems that Pothos is toxic to fish unless you allow the plant to sprout roots in a jar of water before you add the roots only of the plant to your aquarium. There are other plants mentioned in the article, but these are the only two I remember, I'll need to try to find that article again.

[Medkow74]

I wouldn't beat yourself up over 40 PPM especially since it's coming from fertilizer. 

[laritheloud]

Agree with @Mmiller2001, without livestock it's got to be the root tabs leeching into the water column. I'd increase the light (I have a fluval 3.0 on my 55 gallon and model my settings off of Bentley Pascoe's with good results after 4 months) and place the light on risers, which you can DIY out of acrylic pieces or just use a 3D printer. You don't actually need that much CO2 to get really great results, but it sounds like you don't have enough light / light spread for the plants to utilize what you're giving them. I would expect you to have to fertilize at least 2 to 3 times a week with a CO2 setup and high light.

[xXInkedPhoenixX]

I have occupied tanks with no high tech, no ferts that run 40ppm regularly. 

[dasaltemelosguy]

I may be able to help you quantify what you would need insofar as emergent plants for nitrate reduction is concerned.

It may help quantify the amount of say, pothos you'll need by comparing it to mine and scaling it down or up in size. For example, I have two typical, large sized pothos from Home Depot on a 125G, overstocked tank. In addition there are 10 stalks of lucky bamboo. The nitrates are consistently 75% lower than before the emergent plants were installed. I've not seen that tank ever reach 20PPM since the emergent's were installed. 

On the pothos toxicity, the toxin is calcium oxalate. It's actually not toxic but rather, has caustic crystals which can be an irritant. Infamous for irritating cats who chew them. However the crystals are only in the leaves. Calcium oxalate chemically, does exist throughout the plant but not as crystals and there's actually no chance for leaching because it is insoluble at a PH of 4.5 or greater. Even then, if somehow it could dissolve, it must take the form of oxalic acid to dissolve in water which is non-toxic and in most greens anyway. 

Also you can augment the nitrate uptake of the plants using grow lights. It can be quite significant. In addition, switching grow lights to red will drive them further to consume nitrates although they do need white light for the plants health. But I do know someone who switches to red when he needs more nitrate reduction. 

I was part of an informal team of scientists who performed a 1 year test on nitrate reduction via filter media to monitor anaerobic efficacy and with emergent plants. You may read the results here as well as a short on the toxicity. Hope it's of help. 

 

[xXInkedPhoenixX]

@dasaltemelosguy I read your initial post on the Nitrate and pothos/bamboo so I had started my own amateur experiment on my 10g Oto tank. I've seen the Nitrate move even in under a week weirdly though you say your results came 2 weeks later or more- maybe because mine is a smaller tank than yours. How do you manage your bamboo? I can't have 6' stalks! Can you just cut the tops off? Do you trim roots without hurting the plant?

Edited December 25, 2021 by xXInkedPhoenixX

[CalmedByFish]

I'm struggling against nitrates too at the moment, but I recently put fresh root tabs in the tank, and this consistently happens when I add more than 1-2. My knowledge is limited, but I can at least confirm that root tabs can be really bad about sending the nitrates through the roof.

For what it's worth, I'm having the best success at nitrate control in 2 specific scenarios: a tank whose only plant is hornwort that gets daily sun, and a tank whose only plant is frogbit that gets daily sun. I use pothos in other tanks, but for whatever reason, I don't find it to be effective.

[Bev C]

I had problems with my nitrates staying high 60-80 .. But mine was due to right out of the tap water.. Candi told me of the pothos .. went to walmart got a one and between the pothos and weekly cleaning mine is normal now with the fertilizer doze  best wishes 

[dasaltemelosguy]

On 12/24/2021 at 7:37 PM, xXInkedPhoenixX said:

@dasaltemelosguy I read your initial post on the Nitrate and pothos/bamboo so I had started my own amateur experiment on my 10g Oto tank. I've seen the Nitrate move even in under a week weirdly though you say your results came 2 weeks later or more- maybe because mine is a smaller tank than yours. How do you manage your bamboo? I can't have 6' stalks! Can you just cut the tops off? Do you trim roots without hurting the plant?

That is a fast reaction. Ours took longer. At first all the plants drooped in shock and we didn't 'start the clock' until we saw any first growth. Yours must have been healthy out of the gate to get a reaction so quickly. You did something right we didn't!

I know, the height is getting concerning. Right now, they seem to have stopped at about 6.5' but I can't really tell if they just stopped at the edge of the window where the light ceases or if that's about their maximum height. I did have to move a ceiling fan though!

The 'trunk' if you will, never grows. It's the branches that extend and just keep rising. They are quite pliant though and I've seen people train them to spread sideways which seems to work. One I saw, and I wish I had the picture I'm sorry, but the leaves hit the celling so he spread them into a dome shape and they look like little Dragon Blood trees as in Madagascar, to which they are related. It was very pretty if you can find it. 

[dasaltemelosguy]

I forgot to mention the roots. They are bizarrely small, stringy and even after two years and 6+' in height, they are not even 2" long. I just wanted to mention anecdotally that my 120 has severums and the pothos in that tank grows significantly slower then the 125 because the severums keep eating pothos roots! I also added 4 stalks of bamboo but not buried, suspended from the top grid as I saw someone here do it and I thought it looked quite cool. In a day, the severums ate all the roots off and the stalks died! The stalks buried in the gravel of course are safe but I've actually had to add another pothos on their tank after about a year because they eat the roots so much! 

[xXInkedPhoenixX]

@dasaltemelosguy well I'd owned my Lucky Bamboo for at least 4 years maybe a bit longer already- I'd repotted them a year or so ago in aquarium substrate because it was what I had on hand. So that was what got put in my tank- and since they, and my Pothos and Spider plant experimentation plants are with Otos- they don't have any danger of getting eaten- maybe just cleaned a lot haha. When I say I saw the Nitrate move- it went from 40-80 (the reds are hard to tell apart on API master test kit) to not so clearly red and partly orange- so I'm looking forward to my testing next week to see if we can get a full on orange. The plant is clearly happy because its roots have outstretched and the plant on top is spreading out.  I'm documenting on my Accidental Oto journal. 

Edited December 25, 2021 by xXInkedPhoenixX

[dasaltemelosguy]

Wow, that's quite a drop. Just fantastic. Over time I tried monstera and anthurium and peace lilies, but these two plants (pothos and bamboo) consistently starved them out of nutrients. I tried to supplement but I finally gave up and just use these now. 

They surprised us as well. We assumed the faster growing plants would be the big nutrient consumers but as you said, these seem to begin quite slowly and then its starts consuming nutrients like mad.

How tall did yours get? You've had them longer than I have and mine are presently 6 1/2'.  Will it stop or do I need a skylight!

Thanks for the information. I'll definitely check out your journal!

[xXInkedPhoenixX]

@dasaltemelosguy the nitrate experiment with bamboo starts with page 4 so you don't have to wade through my Oto entries and are sporadic so far. I posted a pic of what my bamboo looked like in the pot before I tore them out. They're not big only about 3' root to tip of leaves, part of that might be lack of nutrients and not a lot of light. They're not getting much light now but plenty of nitrate since it's been consistently 40ppm for months. I'm not sure bamboo really stops, that's my concern. Never plant it in the ground unless you want a yard full of bamboo and own a Panda bear. It's prolific. I guess one could just cut the tops off and put them in water to propogate more, I might have to try that once mine grow a bit- I've never tried!