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Strange, I believe Miracle-Gro Organic Choice potting mix consist of a blend of sphagnum peat moss, composted bark fines and natural fertilizer. That`s why I tried to find something similar here in Norway.
I would not try to second-guess soils and ingredients. Just get an ordinary, inexpensive potting mix that people in Norway use to grow houseplants. I'm going to assume that any commercial potting soil will contain enough nutrients to get started. Later on, if you see nutrient deficiencies, you can consider fertilizers.
 

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#1 The question is how much nitrogen do you want in your soil?

Quoted from Aquarium Science – The Science of Aquariums : "Most (but not all) rooted “vascular” plants have been shown by testing to absorb phosphorus and iron from their roots much better than from their leaves. Most (but not all) vascular rooted plants also absorb potassium and nitrogen much better through their leaves".

#2 So, if we would like to follow this "guideline" it would be vice to have a soil rich in carbon, iron, and phosphate, while the water layer should contain potassium and nitrogen, true or false?

#3 An organic carbon-rich soil mixed with bonemeal or fish meal to add phosphate combined with iron sulfate would do it or?
#1 Not too important. Commercial soils designed for houseplants should have enough N. Let fish waste (via fishfood) provide the water ammonia plants like.

#2 Yes. You definitely want soil to contain phosphates and micronutrients. Some carbon is okay to provide CO2 via decomposition, but too much and soil easily goes anaerobic. Ideally, I would use a forest or agricultural soil with 5-10% organic matter, but most people don't have access to good mineral soils. I would try to work with potting soils with their less than ideal 60-80% organic matter. Mix them 50:50 with STS or sand. Or mineralize them via Michael's procedure to decrease the decomposition. As my book shows (Fig VIII-5, p. 130), even acidic soils become neutral over time following submergence (e.g., one soil with a starting pH of 4.5 was ~6.2 pH within 3 weeks).

#3 I think a little bone meal mixed with the soil is good and I use it. It contains not only Ca/Mg and carbonates but P, which is really important to have in the soil. I would not add iron sulfate to a potting soil. Both iron and sulfates in potting soils can cause problems. A decent potting soil should contain enough Fe.
 

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I would use small amounts of bone meal.

Potting soil containing peat is fine; it is processed and fertilized. You have to trust the manufacturer to sell a product--whatever manure, bird dropping, compost it contains-- that will grow plants. Otherwise, the company would not stay in business.

Pure 'peat moss' sold in bags labeled peat moss, I would never use. Too acidic, no iron, no P, etc.
 

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Also, make sure your water has enough Ca, Mg, and K, and bicarbonates, the hardwater nutrients. GH should be above 5. KH above 4.
I hope that you have read my book, not just getting dis-jointed second- and third-hand tips off the Internet.
It helps to have an understanding of the interactions between plants, submerged soils, water, etc.
 

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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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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?
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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:LOL: I do not have any pure manure tanks at the moment :LOL: . However, some manure is usually often added to commercial garden soil if you read the label at the back :geek:. Since it smells of manure in tank 2, I was wondering if that smell usually gets stronger or weaker with time....but I guess no one have had that experience here. If it gets stronger I will tear down tank 2 also.
Manure should be well-composted before it is sold to people as an ingredient in potting soil. Doesn't matter whether the manure is originally from chickens, cows, or what-not.
If the soil is growing plants, I wouldn't worry about the smell. Maybe it is a stray worm that's decomposing at the bottom? And whatever it is, the smell probably will decrease as it eventually decomposes. I certainly wouldn't tear down a tank because of it. Just increase aeration and do a water change.
If it truly is manure, you should be able to confirm its presence by measuring ammonia.

You do know that nitrogen is a major plant nutrient? Your plants in Tank #3 may be nitrogen deficient, since the substrate has none and you haven't added fish/fishfood. Same goes for phosphate.
 

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The plant looks good to me. If it is growing well, I would leave it alone. It could be harmless red algae or metal sulfide deposits on the stems. Both dark colored. The Tiger soil could have some excess metal micronutrients that are reacting with stem leachates and precipitating. Only if the roots are black and mushy (decomposing) would I remove this nice plant.
 

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This looks like a classic symptom of iron deficiency--yellowing of the youngest leaves. Iron is the one nutrient that can hold back floating plants that depend on water iron. (Rooted plants can get iron from the soil.) Iron is the one nutrient that is often deficient in the water, because it forms iron oxides and precipitates out making it unavailable to plants and algae.

I purchased FeEDTA powder. I quickly make a fresh stock solution of a pinch (200 mg?) in a cup of water and then add this cup to every 10 gallons of tank water. Doesn't have to be exact. I might add it just once or twice a month.
 

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Edited on 1/28/23: I looked through my references and all the aquatic botanists use chelated iron (e.g., FeEDTA). Chelated iron will stay in solution longer than the non-chelated ferrous iron that you have, especially at that high pH. I vaguely remember reading that ferrous iron will get oxidized within minutes at pH 8 while it will last a few hours at pH 6. Chelated iron, in contrast, will stay in solution a few days once you add it to the tank.

Also, remember that DOC (dissolved organic carbon) also chelates iron. Some of my tanks never need iron addition, and others sometimes need it for floating plants.

FeSO4 may work, but you will need to add it more frequently and in tiny doses (make a stock solution with just a sprinkling--50 mg-- and use it immediately.). If you get a plant response (new leaves are greener) that will tell you if it is working. If it doesn't work, then get chelated iron powder or a trace element fertilizer. I wouldn't dump FeSO4 into the tank as it contains sulfates and you don't want to load up your tank with sulfates.

I wouldn't worry about the pH, especially with the guppy and snail additions. Overall, your tank is nice.
 
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