# What is Consuming all my Nitrates!?



## silasvirus82 (Aug 12, 2019)

I've had my tank setup now for about a year, and four months ago I experienced a major crash with all my plants. Throughout this time I've been dosing Flourish and Excel per recommended dosing, but started dosing dry ferts given the issue at-hand. For purposes of this discussion, I have had four or five categories of plants: Anuibus, dwarf sag/val, lotus, alt mini, and swords. My lighting is probably considered medium, and my substrate consists of black diamond blasting media and eco-complete. I've also been placing osmocote plus capsules periodically, especially in the vals and swords. What I'm assuming has happened is my plants had been thriving on the eco-complete, and when those nutrients depleted the plants crashed. In the past four months I've been playing catchup trying to get a dosing regimen that would maintain 20-40 ppm nitrates. It seems like the more I dose the faster my "tank" is consuming them. I'm literally putting in heaping tablespoon of KNO3 every other day now, and my nitrates jump up to 40-60 ppm, then are zero by day two. Based on my research for a 125 gallon aquarium, this is A LOT! At this dosage my plants are rebounding SLOWLY, but something seems to be consuming nitrates at a ridiculous rate. I had two canister filters plus a 29 gallon sump for filtration, but have recently removed one canister filter to see what happens. The anuibus grew very slowly the first 8 months, probably due to under fertilization, but everything else exploded with the exception of alt mini which I cannot keep alive. The first plants to show signs of the crash were the dwarf sag, then the vals, lotus, and swords followed in that order. Then I started dosing dry ferts, namely KNO3, but also K2SO4 and KpPO4 at times. The sag were the first to rebound, and the anuibus have been growing like crazy. I can see the vals and lotus trying to rebound, but they are nowhere near their former glory. The two sword plants have basically just stalled out.

I guess my question is, is this a normal amount of dosing for a low tech tank given the plant list and lighting? It seems like something about my setup is consuming crazy amounts of nitrate. Link to my setup is here for reference, but no current pics since it's sorta sad to look at. https://www.plantedtank.net/forums/12-tank-journals/1297953-125-low-tech-rock-garden.html#post11258317


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## Bunsen Honeydew (Feb 21, 2017)

Are you dosing iron? If you are already dry dosing, I'd get some CSM+B too.

Are you testing your nitrate after dosing too? I know it is quite common to get really low nitrate results accidentally with the liquid tests, but if you are getting good values after dosing that's not the problem. I have ran a few low tech tanks that consumed enough nitrate that I could never see readable nitrate except after dosing.

How do your leaves look? That may lend some insight into the deficiency that you are experiencing. 

I am curious to see what this ends up being. I had a 92 corner that had Vals threatening to take it over, then they just stopped all of a sudden. Then the rotala took over that role. Another thing I have noticed with swords is sometimes, especially when newish, they have just stopped growing fir a month or two, then exploded. I had one that would grow another 18"+ leaf every 3 days do this too me last year. When I broke down that tank, the sword had a root system that was 4-5 ft long. I presumed that the dormancy of the sword was the plant growing out it's root system rather than pushing leaves.

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## silasvirus82 (Aug 12, 2019)

Bunsen Honeydew said:


> Are you dosing iron? If you are already dry dosing, I'd get some CSM+B too.
> 
> Are you testing your nitrate after dosing too? I know it is quite common to get really low nitrate results accidentally with the liquid tests, but if you are getting good values after dosing that's not the problem. I have ran a few low tech tanks that consumed enough nitrate that I could never see readable nitrate except after dosing.
> 
> ...


I am dosing iron, but not frequently. What is the correlation with iron and nitrates? I'm still dosing Flourish, so all micro should be accounted for.

I'm testing nitrates constantly since the swings are so dramatic. Almost always when I test before ferts nitrates are zero. After a heaping tablespoon they jump up to 40-60 ppm. Within a day they typically drop to 10-20, and by the second day back to zero.

New growth on all plants looks good, but if I miss a dose for more than a day or two things start going south quickly. The swords have never exploded with growth, and they are both over six months old. One is a purple knight, so no surprise there, but the other red rubin should be doing much better.


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## varanidguy (Sep 8, 2017)

Are you using large amounts of lava rock in a low flow portion of a filter? Sometimes when conditions are just right, there are reports of lava rock growing anaerobic bacteria - if that happened, combined with plants consuming some, and maybe some deep, low oxygen pockets in your substrate...perhaps you got lucky/unlucky and created the perfect storm.


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## silasvirus82 (Aug 12, 2019)

varanidguy said:


> Are you using large amounts of lava rock in a low flow portion of a filter? Sometimes when conditions are just right, there are reports of lava rock growing anaerobic bacteria - if that happened, combined with plants consuming some, and maybe some deep, low oxygen pockets in your substrate...perhaps you got lucky/unlucky and created the perfect storm.


I have all of that going on. Large mass of lava rock in the sump and deep substrate on one side. I can fix the lava rock issue, but I have feeling the deep substrate hill I have on one side is the bigger culprit. I'm not seeing any large pockets of gas or bubbles though. Occasionally the large piece of driftwood I have will burp our a series of bubbbles, but nothing from the hill. FYI, I layered the hill with course gravel mostly, then a 2" layer of eco-complete, then 2" of sand. The lava rock in my sump is aerated from below, so I don't think that is the source either, but then again I'm here asking questions.


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## varanidguy (Sep 8, 2017)

silasvirus82 said:


> I have all of that going on. Large mass of lava rock in the sump and deep substrate on one side. I can fix the lava rock issue, but I have feeling the deep substrate hill I have on one side is the bigger culprit. I'm not seeing any large pockets of gas or bubbles though. Occasionally the large piece of driftwood I have will burp our a series of bubbbles, but nothing from the hill. FYI, I layered the hill with course gravel mostly, then a 2" layer of eco-complete, then 2" of sand. The lava rock in my sump is aerated from below, so I don't think that is the source either, but then again I'm here asking questions.


Well, I cannot tell you with absolute certainty, as I'm not a scientist, but it sounds like a viable cause to losing the nitrates.


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## PlantedRich (Jul 21, 2010)

Have you considered letting the plants show you what nutrient they might need? I find it takes a bit of both testing and looking at the plants to see what might be going on . I might suggest looking for one of the plant nutrient charts for something that matches what you see. If the charts don't show nitrate lacking, then I might look at what problems/questions there might be with the way the nitrate is used or the testing done.
https://www.google.com/search?q=aqu...hUE04MKHWesDrsQ9QEIZzAH#imgrc=Vn4aQwqnj0DI2M:


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## Bunsen Honeydew (Feb 21, 2017)

varanidguy said:


> Well, I cannot tell you with absolute certainty, as I'm not a scientist, but it sounds like a viable cause to losing the nitrates.


Haha, scientists will never tell anyone anything with absolute certainty. 

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## AbbeysDad (Apr 13, 2016)

As with live rock and deep sand in SW, it is possible that you cultured anoxic or anaerobic bacteria that converts nitrates into nitrogen gas. This is something I've been trying to do for some time in my 110g stock tank w/40g sump. However, it seems that this is often more difficult in FW than SW.

I'm not a fan of Excel. Glutaraldehyde kills algae and some plants (jungle val can be especially sensitive). I have used Flourish Comprehensive with good results, but switched a few months ago for cost reasons.

Some of your plants are slow growers and amazon swords are heavy root feeders. I've never tried osmocote gel caps - some rave about them, others say that terrestrial ferts just don't belong in the aquarium. I'm also generally uninformed about dry ferts, although lately I've been using Select Aquatics Rapid Grow fertilizer. Results so far seem promising.

Hmm...Looking back over the above it looks like I haven't helped much! I'm a fishkeeper and really just use plants for naturalization and an aid in water purification. I primarily rely on fast growing floating plants, although my low tech planted display tank (avitar) often gets oohs and ahhs from visitors.

Good luck in sorting out your issues. I've found that the biggest additive we need for planted tanks is patience!!!


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## silasvirus82 (Aug 12, 2019)

Still can't figure this out, but I'm dosing more KNO3 than ever and I can't get nitrates to stay above zero for more than 24 hours. If I have anaerobic bacteria consuming all my nitrates wouldn't I be seeing a ton of nitrogen gas bubbles? I don't see any bubbles at all! Is it possible that my driftwood is somehow the issue? I'm really about to give up with plants and just focus on the fish which are doing great. Anubias is doing fine, but that's about it. Vals, sag, swords, lotus all just barely hanging on because I cannot keep nitrates in this tank.


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## Bunsen Honeydew (Feb 21, 2017)

Well, it does seem that something is consuming them. I'm with you in expecting some bubbles if you had anaerobic denitrification happening. I am inclined to think that this isn't happening simply because if you were diffusing enough nitrate into the deep sand bed to consume them at the rates you are seeing, you'd also be diffusing in enough oxygen that you wouldn't have the anaerobic action happening. Is it impossible that you are consuming nitrogen at this rate with your plant load? Are you monitoring your other macros? Are you adding your other macros to keep them in the same ratio with the nitrates that you are adding? Keeping your NPK ratios consistent won't make you consume nitrate slower, but maybe it will get the plants looking better? If you are going to be dosing, might as well look good, no?


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## silasvirus82 (Aug 12, 2019)

Bunsen Honeydew said:


> Well, it does seem that something is consuming them. I'm with you in expecting some bubbles if you had anaerobic denitrification happening. I am inclined to think that this isn't happening simply because if you were diffusing enough nitrate into the deep sand bed to consume them at the rates you are seeing, you'd also be diffusing in enough oxygen that you wouldn't have the anaerobic action happening. Is it impossible that you are consuming nitrogen at this rate with your plant load? Are you monitoring your other macros? Are you adding your other macros to keep them in the same ratio with the nitrates that you are adding? Keeping your NPK ratios consistent won't make you consume nitrate slower, but maybe it will get the plants looking better? If you are going to be dosing, might as well look good, no?


I'm probably dosing 5-7 tablespoons every other day. Is it possible that my plants are consuming that much, I don't know?

I don't see any other nutrient deficiencies, but if I don't keep up with the nitrates everything dies off at a rapid rate. For "everything else" I'm using the recommended dosing of flourish.


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## Bunsen Honeydew (Feb 21, 2017)

That's crazy, 6 tablespoons in a 125 is more than 150 ppm. I mean, if its working so be it, but you may want to invest in a dosing pump at this rate.


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## rzn7z7 (Aug 17, 2013)

What test kit are you using to measure nitrates? Any chance it expired?


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## monkeyruler90 (Apr 13, 2008)

what is your fish load in this tank? how heavy is your feeding?


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## silasvirus82 (Aug 12, 2019)

In answer to a few posts, I've checked my testing kit, twice, not the issue. I have no problem getting a reading on nitrates after a heavy dose, but the next morning its back to zero. I'll keep dosing at the rates I'm doing, but it just seems so excessive and possibly getting worse. I'm trying to figure out the WHY! Fish load is ten full size platinum angelfish, four L144 plecos almost full grown, and a half dozen electric blue rams. I've also attempted to keep nerite snails in this tank on three occasions, not that algae has been an issue, but something is killing those off as well. I'm using well water and treating for heavy metals, so can't figure that one out either. Originally I was mixing 50/50 RO water with my well water and the snails did fine, but have since just been using well water exclusively and the snails won't last a day now. The fish are doing great, constantly spawning and even have about 100 EBR fry in my 29 gallon quarantine tank right now. I feed twice per day, once by auto feeder and once at night that is usually a treat.

I'll post some pictures later if that helps.

Also, keep in mind I have a 30 gallon sump plus I'm running a canister filter, so my total volume is closer to 150.


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## silasvirus82 (Aug 12, 2019)

Some pictures for those interested. First pic highlights the sag and vals in various states of health. You can see the mixture of recent die-off and growth based on nitrogen deficiency. The vals were glorious until they depleted the nutrients from my substrate and have been struggling ever since.










Next up are some pics of my anuibus, purple knight sword, lotus, and remaining vals/sag. The anuibus are constantly sprouting new leaves and for the most part look fine imo. The purple knight swords had never looked good and that was somewhat expected in a low tech setup. The lotus was once 5x larger and lush, and is starting to make a comeback. I had a red tiger lotus as well that has died off completely however.



















Final pic is the current sad state of my red rubin sword which has never really taken off and all the other plants mentioned before in varying states of decay/rebound.










I dosed 5 tablespoons of KNO3 yesterday after work and to no surprise my test kit showed zero this morning. Before bed it was about 50-60 ppm.

One thing I'm considering is taking out the majority of my plants replacing the substrate. I'm hoping that if I continue to dose at my current levels that the plants will rebound quickly given some fresh substrate. Any other ideas or suggestions of what I can do?


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## Deanna (Feb 15, 2017)

It is interesting, as others have said. You appear to definitely have a de-nitrification factory going on somewhere in your tank. I lean more heavily toward the lava rock in your filter/sump, despite the O2 under it. The idea of lava rock as a de-nitrifier is that the deep tunnels simply prevent O2 from getting in and I don’t think that O2 can be readily forced into it. You could try removing it for a few days and see if NO3 changes then, if it doesn’t, look deeper (figuratively and literally) into your substrate. If you figure out how you created it (assuming there is no nitrate absorbing material anywhere), let us know. Some members would kill to make one of their own.

There is no way that plants will uptake that quantity of NO3. If you think, by noting their health, that plants are struggling due to nitrogen deficiency, you can also dose urea in place of the NO3. That way, you will be sure of getting N to the plants (make sure that you also dose a tiny amount of nickel if you decide to use urea). It’s usually best, though, to have at least a little NO3, along with the urea, since some plants do benefit from NO3, but they will probably get the little they need even though your testing may not show it.


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## silasvirus82 (Aug 12, 2019)

Deanna said:


> It is interesting, as others have said. You appear to definitely have a de-nitrification factory going on somewhere in your tank. I lean more heavily toward the lava rock in your filter/sump, despite the O2 under it. The idea of lava rock as a de-nitrifier is that the deep tunnels simply prevent O2 from getting in and I don’t think that O2 can be readily forced into it. You could try removing it for a few days and see if NO3 changes then, if it doesn’t, look deeper (figuratively and literally) into your substrate. If you figure out how you created it (assuming there is no nitrate absorbing material anywhere), let us know. Some members would kill to make one of their own.
> 
> There is no way that plants will uptake that quantity of NO3. If you think, by noting their health, that plants are struggling due to nitrogen deficiency, you can also dose urea in place of the NO3. That way, you will be sure of getting N to the plants (make sure that you also dose a tiny amount of nickel if you decide to use urea). It’s usually best, though, to have at least a little NO3, along with the urea, since some plants do benefit from NO3, but they will probably get the little they need even though your testing may not show it.


Are you suggesting that I pee in my tank? I mean, I guess we can try that, lol. Seriously though, didn't know that was a thing and I'll check it out. Also, thank you for the lava rock suggestion, and one I will definitely try out immediately. Others have used lava rock in their filters and not had this issue I think, but perhaps something special is going on there.

What could be a nitrate absorbing material? I'm using basalt for my base substrate and rocks, with layers of eco-complete and bdbm over the top of that. Nothing special there other than the depths perhaps. The hill on the right side is probably a foot thick on the back-right side glass, but tapers of quickly moving front-left. I've suspected for a while that anaerobic bacteria might have colonized in that hill, but I'd expect to see bubbles and that is not the case. The only other hardscape is the giant piece of driftwood, and I have no idea what exactly that is. I found that piece on a lake bank.


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## monkeyruler90 (Apr 13, 2008)

what about using root tabs near the plants. the roots will take it vs dosing in the water column. might help out.


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## silasvirus82 (Aug 12, 2019)

monkeyruler90 said:


> what about using root tabs near the plants. the roots will take it vs dosing in the water column. might help out.


I am using root tabs. DYI osmocote gel caps periodically. I'm not sure how many I should be using, but I've been putting 3-4 caps around the swords every few months and at least a dozen more throughout the vals and sag. I have not seen any noticeable effect from them, but I do see a dramatic effect when I forget or can't dose KNO3 for three or four days.


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## Deanna (Feb 15, 2017)

silasvirus82 said:


> Are you suggesting that I pee in my tank? I mean, I guess we can try that, lol. Seriously though, didn't know that was a thing and I'll check it out. Also, thank you for the lava rock suggestion, and one I will definitely try out immediately. Others have used lava rock in their filters and not had this issue I think, but perhaps something special is going on there.
> 
> What could be a nitrate absorbing material? I'm using basalt for my base substrate and rocks, with layers of eco-complete and bdbm over the top of that. Nothing special there other than the depths perhaps. The hill on the right side is probably a foot thick on the back-right side glass, but tapers of quickly moving front-left. I've suspected for a while that anaerobic bacteria might have colonized in that hill, but I'd expect to see bubbles and that is not the case. The only other hardscape is the giant piece of driftwood, and I have no idea what exactly that is. I found that piece on a lake bank.


You may laugh, but it has actually - supposedly - been tried, along with other foolish things of similar ilk. Don't do it, though, as there are other ways to introduce urea. In fact, if I recall correctly, urea is the dominant nitrogen source used in farming worldwide (it's cheap). This thread, by @Edward, will give you all you need to know about urea use in an aquarium: https://www.plantedtank.net/forums/11-fertilizers-water-parameters/1026985-urea-co-nh2-2-a.html

People, sometimes and without knowing, will put chemical media in their filter that will absorb nitrate. A one-foot thick substrate area is a always a concern. However, I'm not sure that any de-nitrification going on in a tank can convert that much NO3 so quickly, but I don't actually know how efficient such conversion can be.


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## silasvirus82 (Aug 12, 2019)

I think I finally figured it out. Decided to change out the filter pads in my canister filter and while I had it apart took all the bio media out to see if that might be the issue. Dosed my tank two days ago and holding at 20-30 ppm! I can't believe my canister filter was the culprit, but another day or two will confirm for sure. That filter was doing it's job!


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## varanidguy (Sep 8, 2017)

silasvirus82 said:


> I think I finally figured it out. Decided to change out the filter pads in my canister filter and while I had it apart took all the bio media out to see if that might be the issue. Dosed my tank two days ago and holding at 20-30 ppm! I can't believe my canister filter was the culprit, but another day or two will confirm for sure. That filter was doing it's job!


What media were you using?

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## Bunsen Honeydew (Feb 21, 2017)

I'm glad things are returning to normal, but that is a curious solution. Was the canister very restricted? (anoxic?)


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## silasvirus82 (Aug 12, 2019)

I'm using a Penn Plax Cascade 1500 and 1200, only the 1500 for the past month. The trays were a mix of bio sponge, Fluval ceramic, and filter floss. There was definitely plenty of flow through the filter as I can see the outflow current quite easily.

I'll check my nitrates again when I get home tonight, but if they are anything above zero I've got it. I have been able to hold nitrate levels above zero for more than 24 hours for quite a long time. Maybe I'll order some fresh plants again!


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## Deanna (Feb 15, 2017)

silasvirus82 said:


> I'm using a Penn Plax Cascade 1500 and 1200, only the 1500 for the past month. The trays were a mix of bio sponge, Fluval ceramic, and filter floss. There was definitely plenty of flow through the filter as I can see the outflow current quite easily.
> 
> I'll check my nitrates again when I get home tonight, but if they are anything above zero I've got it. I have been able to hold nitrate levels above zero for more than 24 hours for quite a long time. Maybe I'll order some fresh plants again!


No question about it: ceramic rings can hold denitrifying bacteria, just not as much as lava rock. Did you also remove the lava rock?

Please keep us informed as you go through this.


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## silasvirus82 (Aug 12, 2019)

Deanna said:


> No question about it: ceramic rings can hold denitrifying bacteria, just not as much as lava rock. Did you also remove the lava rock?
> 
> Please keep us informed as you go through this.


Day 3, nitrates slowly dropped off to about 10 ppm from the initial 30-40, that seems totally reasonable. I did remove the lava rock for a time but noticed no change in nitrate consumption, so they are back in. The canister filter was definitely the issue. The ceramic rings and bio sponge are obviously there to consume nitrates, but for whatever reason they were in total overdrive. I can manage a 20-30 ppm drop over three days, but 40 ppm in less than 24 hours was unsustainable. So glad I figured it out and can't wait to get back to planting again.


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## silasvirus82 (Aug 12, 2019)

Almost a full week now and still holding above 5ppm nitrates. Case Closed!


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## monkeyruler90 (Apr 13, 2008)

That's great! how are the plants reacting?


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## silasvirus82 (Aug 12, 2019)

monkeyruler90 said:


> That's great! how are the plants reacting?


I see new growth on everything, but I think the plants have been in shock for so long some may not recover. I replanted my vals this weekend, so starting fresh with those. Couldn't stand the look of a barren tank any longer and those make the biggest difference, plus they're cheap. My tiger lotus completely melted away, but I noticed three new leaves spouting from the bulb and hoping it makes a full recovery. I cut back my red sword and it's shooting up new bright red leaves all over. Maybe I'll finally get some growth! The sag is still in a sad state, but I'm seeing new leaves and shoots so their is still hope for recovery. My anubias is going crazy though. The nana and nana petite have more new leaves than I've ever seen and look incredible. After a few more weeks of recovery I'll post a pic with progress.

On another note, my first spawn of electric blue rams are about sized to sell, and momma just laid more eggs. At least my fish are paying for themselves.


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