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Soil question for the Walstad tank

7203 Views 135 Replies 9 Participants Last post by  Oslo, 
O
Soil consisting of 60% peat moss, 40% composed bark fines and iron sulfate (50g/m3) additive, would it be ok for a Walstad tank even if it has a pH of 4? Or would it be beneficial to have a soil exclusively consisting of either peat moss or compressed bark fines?

Cheers,
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johnwesley0 said:
Of course, the irony here is that the name of this site is Aquatic Plant Central, and this forum is devoted to the idea of adding "soil for plants and plants for soil." The whole point of the Walstad method is to lessen the need for ammonia/ammonium conversion since plants will uptake ammonium directly without creating nitrites. It's still possible to accomplish this in the long run. But it would really mean paying a little less attention to bacteria and maybe adding a lot more plants than you presently have.
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Yes, with more duckweed and more patience I might be able to run both tanks without filter and still get the ammonia/ammonium and nitrite levels under control. So, I did cheat a bit by adding a filter, but I just wanted to speed up the process a bit.

I did some more water tests yesterday.Now both tanks are like this:

NH4 = <0,05
NO2 = >1
NO3 = 80
pH = 7,5-8,0

I also did a 50% water change and poked the soil with a clean bbq stick. The interesting part was that tank1 (with tiger soil) had a lot of air pockets in the soil. Every time I poked I got air bubbles, in contrast, I got zero air bubbles when I did the same with tank 2 (sowing soil). Both tanks were set up two weeks ago.
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dwalstad said:
Enough pictures! :) But beautiful plants. I think you have plenty and they look so healthy. Make sure that that the crown of that big Echinodorus is above the gravel; you've got the crown buried and it may rot. And I would spread out the Hygrophila difformis. You've got all the stems all bunched together.
Not so sure that nitrification is reason for your nitrites. Soil fertilizers? Those high water nitrates could be diffusing into the substrate where MANY ordinary bacteria will convert them to nitrite via 'nitrate respiration' (my book, p. 65). Nitrate respiration in this situation would be a much more common bacterial process than nitrification.
To get your nitrites down, I would do water change to get rid of the nitrates. I assume that those nitrates didn't come from your tapwater. Possibly the soil is the source. Should be a temporary problem, because nitrates don't attach well to soil particles, so eventually they will clear out of the soil and you can get your fish.
I would forget about adding ammonia to your tank. Add a little fishfood. Much safer.
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Yes, thanks for helpful suggestions! I did notice the Echinodorus Argentinensis (grandiflorus) were too deep in the substrate (due to the fact that I added some more gravel to this tank after planting). I pulled it up yesterday, but, maybe I should pull it even further up so it will not rot. Yes, the Hygrophila difformis does not look happy, particular at the bottom. I will spread it like you say, maybe that will help.

Yes, both these soils contain chicken manure in addition one spoon of bone meal that I added in the mix. I did a water test yesterday:

NH4 = <0,05
NO2 = >1
NO3 = 80
pH = between 7,5-8.0
KH = > 6
GH = > 6

So, it looks like ammonia/ammonium went away after adding the floaters in tank 2 (I read that using floaters is a great way to get rid of ammonia/ammonium (0,4-0,6 ppm)). The nitrite levels are another story. Nitrate respiration is an interesting thought, the chicken or the egg theory. These tanks are without fish and fish food. I have not been able to measure very high levels of ammonia/ammonium </= 5 ppm in these tanks. So, my questions is then, can nitrite levels of around 80 ppm arrive from ammonia/ammonium levels of typically 0.2-0.6 ppm (the highest level of ammonia ever measured in these tanks). If not, nitrate has to arise from something else (soil). The question is then, do they arise from nitrite in the soil and undergo nitrification to nitrate or do nitrate arise directly from the soil for later to be converted into nitrite by nitrate respiration? Both, tanks/soils show the same levels of nitrite/nitrate, tank 1 have a lot of air trapped in the soil while tank two has none so far. I did a water 50% water change yesterday, I guess I could do frequent water changes and poke in the soil until the conditions improves. Or, I could sit still in the boat and wait for the nitrification process to overcome the the nitrate respiration process.....
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J
There was an interesting discussion of nitrate respiration in this thread started by @jatcar95 many months ago. It's the first time I'd heard of it. Soil that has been previously exposed to the air for long periods seem especially prone to this:
21G Acrylic NPT | Aquatic Plant Forum (aquaticplantcentral.com)
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Oslo said:
So, my questions is then, can nitrite levels of around 80 ppm arrive from ammonia/ammonium levels of typically 0.2-0.6 ppm (the highest level of ammonia ever measured in these tanks). If not, nitrate has to arise from something else (soil). The question is then, do they arise from nitrite in the soil and undergo nitrification to nitrate or do nitrate arise directly from the soil for later to be converted into nitrite by nitrate respiration?
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Johnwesley0 has provided a good clue as to why your soil might contain high levels of nitrates, for nitrate of 80 ppm in the water are incredibly high. Doubtful they are due to nitrification. Nitrification is a slow process whereas nitrate respiration is a common and very fast process.

In your situation, forget about nitrification. My guess is that your soil is releasing huge amounts of nitrates that are inducing nitrate respiration. Do water changes to remove the nitrates to get rid of the nitrites.

Nitrogen cycling is complicated. Requires patience, but we'll all get there eventually.
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M
To speed up removal of Nitrates, you can use ion exchange resin with strong affinity to Nitrates. I have used is successfully when I experienced Nitrate respiration in one of my tanks.

There are more sophisticated aquaristic products (Szat clear water is the most famous in Eastern Europe), but for your purpose almost any drinking water cleaning resin will work (as long as it has good affinity to NO3). They are regenerated by pure salt (dishwasher) and can be used for many years.
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O
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So, found an old Norwegian article where they have investigated different animal manure and their nitrogen content.

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Chicken manure (hønsegjødsel) seem to contain low amounts of NH4 compared to e.g. pig manure (grisemøkk). Horse manure (hestegjødsel) also contain little NH4, but have less fast available N compared to chicken manure. Small amounts of NH4, both on paper and by testing the water in my tanks further support that my nitrite levels arise from nitrate respiration (NO3-NO2) rather than nitrification (NH4-NO2-NO3). However, even if there is little NH4 in chicken manure compared to other manures it does not say how much in total. In the lower table I found some data claiming that chicken manure in water contain in average 0,40% NH4 and 0,020% NO3.

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Furthermore, I do not know the composition of nitrogen in bone meal (the ammonium - nitrite - nitrate ratio) that I added to the soil. Maybe it is the bone meal that contributes to the peak in nitrate? Any comments on that?

So, Diane are you related to Daniel Walstad who owned a farm here i Oslo? Since your last name is Walstad, I thought maybe you understand norwegian or sweedish?

Last evenings water tests after >50% water change on Friday.

Tank 1
NH4 = <0,05ppm
NO2 = 0,4-0,6
NO3 = 15
PH = 7,5
KH = 6
GH = 6

Tank 2
NH4 = <0,05
N02 = 0,8-1
N03 = 30
PH = 7,5
KH = 6
GH = 6

PS! looking at the measurements, there seem to be a connection between NO3 and NO2. From last measurements, we observed >1 NO2 = 80 NO3. This time we observe that 0.8-1 NO2 = 30 NO3 and 0,4-0,6 NO2 = 15 NO3. Importantly, all these nitrite/nitrate measurements are done with <0,05 NH4 in the water.
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mistergreen
Seems like adding bone meal and manure are a hassle.
if you’re seeing NO3 => NO2 reaction, there might be anaerobic conditions in your substrate.
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J
These measurements are consistent with a 50% water change. The question is whether they are going to shoot back up again or are we simply dealing with conditions that were status quo ante?
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johnwesley0 said:
These measurements are consistent with a 50% water change. The question is whether they are going to shoot back up again or are we simply dealing with conditions that were status quo ante?
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Only time will show, will do another water test tomorrow to see where the nitrite/nitrate levels go. My water lettuce is growing like crazy at least.
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mistergreen said:
Seems like adding bone meal and manure are a hassle.
if you’re seeing NO3 => NO2 reaction, there might be anaerobic conditions in your substrate.
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I am a newbie so I have nothing to compare it against. I guess other people who have used bone meal have to comment on that. Most commercial soils contain either NPK fertilizers or some kind of manure (at least here in Norway). It is not something I have added myself. I do not believe I am the first to measure high nitrite levels after using commercial soils in the tank. As mentioned before, one of the tanks have a lot of air bubbles in the soil the other one has none. I am not sure how to interpret that. Many Norwegians that play with aquariums use NH4Cl to cycle their tanks before buying fish. It usually takes around 3-4 weeks and after daily measurements they find that bacteria for the NH4 to NO2 conversion grow faster than bacteria for the NO2 to NO3 conversion. Anyway, it take some time for the process to occur. My tanks are in its third week now....
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J
Perhaps we should have asked this question earlier: What is it you are trying to accomplish by adding soil to your fish tanks?
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mistergreen
Poke your substrate with a stick and smell if the bubbles smell like rotten eggs. If not, it’s CO2 bubbles.
Your plants look great though.
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johnwesley0 said:
Perhaps we should have asked this question earlier: What is it you are trying to accomplish by adding soil to your fish tanks?
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Did have several tanks when i was younger with only gravel. Wanted to try something different this time to see if I could enhance plant grow without artificial CO2 injection. I do have a third tank also, with just gravel and some commercial fertilizer called aquatic nature fertiplant (Aquatic Nature Fertiplant ABF | Seaflower). I am using this third tank to compare with the two others with garden (tiger and sowing) soil.
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mistergreen said:
Poke your substrate with a stick and smell if the bubbles smell like rotten eggs. If not, it’s CO2 bubbles.
Your plants look great though.
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Good idea! I will do that today.
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So, did a new water test yesterday:

Tank 1
NH4 = <0,05ppm
NO2 = 0,1-0,2
NO3 = 5

Tank 2
NH4 = <0,05
N02 = 0,1-0,2
N03 = 15

NO2 and NO3 levels are decreasing even without water change. I guess NH4 and NO2 will be close to zero in a few days. Since, I am not adding any live stock before X-mas, should I then start to add fish food, aquarium holiday fish food, or NH3 to maintain a high population of beneficial bacteria or is that not necessary?
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dwalstad said:
I would forget about adding ammonia to your tank. Add a little fishfood. Much safer.
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Oslo said:
Since, I am not adding any live stock before X-mas, should I then start to add fish food, aquarium holiday fish food, or NH3 to maintain a high population of beneficial bacteria or is that not necessary?
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You're kind of not listening. Beneficial bacteria have nothing to do with the growth of your plants. Judging from your snapshots, a few more weeks without fish should be fine.
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johnwesley0 said:
You're kind of not listening. Beneficial bacteria have nothing to do with the growth of your plants. Judging from your snapshots, a few more weeks without fish should be fine.
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I know that beneficial bacteria has nothing to do with plant grow ;), but I think it is nice to have some beneficial bacteria when I add guppies into the tank :LOL:
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Oslo said:
I think it is nice to have some beneficial bacteria when I add guppies into the tank
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Why do you say that?
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johnwesley0 said:
Why do you say that?
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So they do not die due to ammonium/nitrite toxicity? I guess a high fish load will increase ammonia/ammonium/nitrite levels in the tank dependent upon the amount of fish and how much you feed them. To then be sure your tank can handle that amount of ammonia/ammonium/nitrite it is ok to have a back up system (filter with beneficial bacteria) in case your plants and your tank can not handle the ammonia/ammonium/nitrite levels.

From one thing to another, I now have bubbles in the soil of both tanks. I did try to smell while I poke the bottom layer, could not smell sulfide/anything. What does that imply? What should the poking be good for, is it necessary? I have a Aquaclear 20 hang on filter on both tanks now.
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Oslo said:
So they do not die due to ammonium/nitrite toxicity? I guess a high fish load will increase ammonia/ammonium/nitrite levels in the tank dependent upon the amount of fish and how much you feed them. To then be sure your tank can handle that amount of ammonia/ammonium/nitrite it is ok to have a back up system (filter with beneficial bacteria) in case your plants and your tank can not handle the ammonia/ammonium/nitrite levels.
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First of all, it is difficult to imagine a higher critical mass of ammonia/ammonium/nitrite than you've already experienced from dumping a bag full of terrestrial soil into your tank and exposing it to water. The fact that all your parameters are headed in the right direction is a huge testament to your healthy plant growth. If you're really worried about bio-load, the solution is to continue what you've been doing which is adding more plants. Hoping that you have enough beneficial bacteria to absorb fish poop is like hoping you have enough ants at a picnic. Just eat the food.

Second of all, as @dwalstad has posted several times, your unusually high nitrite levels were likely not the result of nitrification (beneficial bacteria) but were probably the result of nitrate respiration, a process that was set in motion while the soil was exposed to air.

Third and lastly, be careful what you wish for. The less able your plants are to compete with the beneficial bacteria already in your tank for food, the more you will periodically have to change the water as nitrification levels rise. Plant uptake of ammonia/ammonium results in plant protein. Bacteria just produce a different form of nitrogen.

Oslo said:
From one thing to another, I now have bubbles in the soil of both tanks. I did try to sm,ell while I poke the bottom layer, could not smell sulfide/anything. What does that imply? What should the poking be good for, is it necessary?
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It's probably too early to expect toxic gases to form in your soil. I would consider poking around now rather than later as a preventative measure.
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