Aquatic Plant Forum banner
1 - 20 of 48 Posts

· Registered
50 Posts
Discussion Starter · #1 ·
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?


· Registered
50 Posts
Discussion Starter · #4 ·
Since that soil is 100% organic matter, I suggest that you soak and drain it several times. Then mix it half and half with a high CEC inorganic substrate. I don't know what is available in your location, but here we often use some type of fired clay product.

Thanks for the advise, you mean unfired red clay right? Will this french red clay do the magic?

Font Rectangle Screenshot Parallel Number

· Registered
50 Posts
Discussion Starter · #6 ·
Diana has experimented with a wide variety of potting soils so far with success but peat moss seems to be the universal “no”. I would look for a different soil. Use that bag for house plants.
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.

· Registered
50 Posts
Discussion Starter · #12 · (Edited)
Peat moss have a carbon:nitrogen ratio of 58:1 and bark 100-130:1

autumn leaves30-80:1
wood chips or sawdust100-500:1
mixed paper150-200:1
newspaper or corrugated cardboard560:1

MGOCPM, highly recommended by Walstad as soil in a dirted tank has peat moss and composed bark, same as the soil I found here in Norway (see picture below). If I understand correct, peat moss, composed bark and wood pellets consist primarily of cellulose and lignin, and are mostly carbon.

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".

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?

An organic carbon-rich soil mixed with bonemeal or fish meal to add phosphate combined with iron sulfate would do it or?

In addition, I would like to mix the soil with aragonite sand to increase the KH/pH and make it more friendly for guppies. This sand also works like a natural filter to remove nitrogenous waste (see link: Nature's Ocean Bio-Activ Live Aragonite Sand 9kg - )

CO2 production dependent upon pH, see link:

MGOCPM soil:

View attachment 75802
Font Number Document

The Norwegian rhododendron soil with peat moss, composed bark, and iron, nothing more, nothing less. pH=4

Font Parallel Screenshot Number Rectangle

· Registered
50 Posts
Discussion Starter · #14 · (Edited)
Your missing ingredient is the "slowly available nitrogen" that is included in packaged potting mixes. It is a euphemism for animal (in the above case, poultry) manure. Good luck experimenting with that.
Thank you :) I like a challenge!

Do you think aragonite sand mixed with lava stones would be sufficient as an ammonia removal system in a low tech tank without plants?

· Registered
50 Posts
Discussion Starter · #19 · (Edited)
I have found some products with information about the soil. Could I use one of these?

A. Pottering soil:
Size: 0-35 mm
pH-value: 6,0
Organic content: >60%
Density 450 kg/m3
Total nitrogen (EN 13654-1) 2400 mg/l

Composition: light peat moss (H2-4), dark peat moss (H6-8), sand, limestone, fertilizers

Additions pr. m3:
Limestone: 3,5 kg
Dolomitt: 2 kg
Chicken manure: 5 kg
Fertilizer NPK 12-4-18: 1 kg

Nutrition in g/m3:
Bor (B):0,6
Kobber (Cu):0,85
Fosfor (P):95
Jern (Fe):3
Kalium (K):280
Mangan (Mn):4,25
Kalsium (Ca):1950
Molybden (Mo): 0,03
Magnesium (Mg):260
Sink (Zn):2,9
Svovel (S):120

B. Sowing soil
Size: 0-15mm
Organic content: >40%
Density: 440 kg/m³
pH-value: pH 5,5 - 6,5
Totalnitrogen (EN 13654-1 1500 mg/l)

Composition: light peat moss (H2-H4), dark peat moss (H6-H8), sand, organic chicken manure, limestone, kalimagnesia.

Aditions pr. m3:
Magnesium and limestone: 5,5 kg
Chicken manure: 2 kg
Kalimagnesia/patenkail (potassium sulfate and magnesium sulfate): 0,3 kg

Nutrition, mg/l:
Nitrogen(N)/(NO3-N+NH4-N): 80
Bor (B): 0,2
Kobber (Cu): 0,6
Fosfor (P): 25
Jern (Fe): 50
Kalium (K): 150
Mangan (Mn): 7
Kalsium (Ca): 225
Molybden (Mo): 0,1
Magnesium (Mg): 220
Sink (Zn): 2
Svovel (S): 60

C. Plant soil
Size 0-35 mm
pH-value: 6,0
Organic content >80%
Density: 390 kg/m3
Total nitrogen (EN 13654-1) 1500 mg/l

Composition: light peat moss (H2-4), dark peat moss (H6-8), sand, limestone, fertilizer

Additions pr. m3:
Limetone: 3 kg
Dolomit: 2 kg
Fertilizer NPK 11-5-18: 1 kg

Nutrition: mg/l:
Nitrogen(N)/(NO3-N+NH4-N): 110
Bor (B): 0,3
Kobber (Cu): 0,5
Fosfor (P): 45
Jern (Fe): 40
Kalium (K): 210
Mangan (Mn): 19
Kalsium (Ca): 200
Molybden (Mo): 0,2
Magnesium (Mg): 230
Sink (Zn): 3,5
Svovel (S): 150

D. Top soil
Natural sand, garden compost, and some kind of animal (unknown) manure
For upper lawn layer and sowing of grass, for flowers and plants.
Has huge amounts of "reserve" plant nutrition.
Deposit nutrition over a long time period.
High pH, no need for limestone products.
Recommend to add nitrogen fertilizer dependent upon plant grow wanted
Size: 0 - 10 mm
Density: 955 kg/m3
pH 7,5 - 8,5

Nitrogen (NH 4 - N + NO 3 - N) 4,8 + 15,01 mg/L
Fosfor (P) 21,7 mg/100 g
Kalium (K) 100 mg/100 g
Magnesium (Mg) 39 mg/100 g
Kalsium (Ca) 378 mg/100 g

E. "Tiger soil"
Garden compost, Vermicompost, sand, chicken manure
For outdoor use, can contain worms, for plants in pots, to improve current soil, use nitrogen fertilizer after own choice.
Size: 0 - 10 mm
Density: 580 kg/m3
pH 7,6

Nutrition in mg/L
Nitrogen (N) 3000
Natrium (Na) 46
Ammonium (NH4) 0,23
Sulfat (SO4)10
Nitrat (NO3) 13
Bor (B) 1,2
Fosfor (P) 4,2
Kobber (Cu) 1,7
Kalium (K) 1200
Jern (Fe) 87
Kalsium (Ca) 5300
Mangan (Mn) 3,7
Magnesium (Mg) 160
Sink (Zn) 15

F. Oslo soil
Leafs, branches and grass
For plants, flowers, kitchen garden, light structure, high pH, deposit nutrition over a long time, recommend addition of nitrogen fertilizer after needs.
Size: 0 - 10 mm
pH 7,5 – 8,5
C/N: 17,5

Ammonium (NH4) 8,3
Nitrat (NO3) 56
Bor (B) 1,5
Fosfor (P) 36
Kobber (Cu) 1,7
Kalium (K) 2100
Jern (Fe) 26,3
Kalsium (Ca) 2574
Mangan (Mn) 2,8
Magnesium (Mg) 141
Sink (Zn) 16
Svovel (S) 49

· Registered
50 Posts
Discussion Starter · #21 ·
Found some more info about the top soil and it seems like some unknown animal manure have been added to this soil too. Interesting, when comparing ingredients between the soils we can see that the oslo soil (ammonium/nitrate PK = 21,8 mg/L - 217 mg/g - 754 mg/g) contain much more NPK nutrition than e.g. top soil (ammonium/nitrate PK = 19,81 mg/L - 21,7 mg/g - 100 mg/g). Numbers for the tiger soil would be = 13,23mg/L - 4,2 mg/g? - 1200 mg/g?. So, how would you choose between these? Very high amounts of Mg and Ca would maybe be a problem in the oslo soil? Top soil, oslo soil and tiger soil are all without peat and at least oslo and top soil have been produced by a hot composting process. Unfortunate, I do not know the amount of organic content in these soils.

Dwalstad mentioned forest or agricultural soil with 5-10% organic matter. I have access to both in some way, but how do I choose between the different types of e.g. forest soil. Would I choose the soil found in spruce woods, beech forest, pine forest, birch forest, flower meadow etc? A problem with agricultural soil found outside is that you have no idea what the farmer have used to fertilize it.

· Registered
50 Posts
Discussion Starter · #23 ·
I am a little puzzled by your question "Do you think aragonite sand mixed with lava stones would be sufficient as an ammonia removal system in a low tech tank without plants?". Are you planning a planted tank, or a tank without plants?

Maybe both, I am curious of nature and would be interested in finding the golden balance between fish load and a low tech ammonia system without using a filter. E.g. would it be possible to keep ammonia levels under control in a fish tank without plants and filter by using only an airstone/power head combined with suitable gravel/stones that contain bacteria for converting ammonia to nitrate (denitrification). If yes, where would that line go? 2 guppies, 5 guppies, 10 guppies, 50 guppies? This would be highly dependent upon feeding protocol and water changes.

· Registered
50 Posts
Discussion Starter · #24 ·
Aren't you overthinking it a little? :) I would take the most "simple" soil I could find - ordinary potting mix with no wetting additives and call it a day. You could also do an experiment with a couple of bigger jars (~5-10l) and use different soil in each to see how they behave.. :)

Yes, I guess I have to do that, do an experiment on my own as I am unable to choose a soil as they all have additives. I also get confused by all the different opinions at this and other sites.

· Registered
50 Posts
Discussion Starter · #26 ·
Ammonia or nitrite won't be a problem, cichlid tanks run without any plants just fine. Nitrates have to be removed by water changes. Soil substrate in such case doesn't make much sense. I would expect that bare tank without a filter will take longer to "cycle", so I would start slow with a few fish specimen (whose health might get impacted negatively by initially elevated ammonia/nitrites, so don't get too attached to them🙂).
So, soil substrates like aragonite and lava stones will not be able to remove much ammonia from fish waste and food? Even if I have good water circulation and oxygen rich water?

· Registered
50 Posts
Discussion Starter · #29 · (Edited)
Ammonia or nitrite won't be a problem, cichlid tanks run without any plants just fine. Nitrates have to be removed by water changes. Soil substrate in such case doesn't make much sense. I would expect that bare tank without a filter will take longer to "cycle", so I would start slow with a few fish specimen (whose health might get impacted negatively by initially elevated ammonia/nitrites, so don't get too attached to them🙂).
Sure, if I go with aragonite gravel and lava stones I can combine it with floating plants and or moss to remove the nitrate. I also have concentrated NH3 to grow bacteria prior to adding fish and plants. I guess it will be important to have water circulation in lower levels of the tank with oxygen rich water to convert ammonia to nitrate (as this process is oxygen dependent) and maintain a healthy population of beneficial bacteria. An alternative to the walstad metod without nutrition rich soil/substrate, high CO2 production, and root plants.

· Registered
50 Posts
Discussion Starter · #30 · (Edited)
Any of the forest soils will be fine. They will not need any pretreatment except for removal of any large pieces of organic matter to prevent floating. Use one of those and set your mind at ease.
OK, how can I be sure that the soil from any kind of forest will contain a good nutritional mix for my water plants?

I have some soils that I would like to test out. One with pure peat moss (100% organic), one with some peat moss (>40 organic) and two without peat moss (44 and 45% organic). Want to check pH and ammonia levels etc. and grow potential (I have added some floating plants and a small root plant into each bottle - not shown in the picture). The two soils without peat moss are the "oslo" and the "tiger soil", containing different amount of ammonia etc. Would you choose the "oslo" soil which has the highest amounts of potassium, phosphate, and free ammonia/nitrate or "tiger" with less potassium, phosphate, and free ammonia/nitrate?

Liquid Fluid Rectangle Drink Glass

Font Paper product Paper Document
Font Book Publication Paper Paper product
Sleeve Font Material property Paper Transparency

· Registered
50 Posts
Discussion Starter · #33 · (Edited)
So, I did set up two tanks on Friday. Any advise for a newbie? Do I need more light or a heater?
Water specs after thee days: pH= 7-7,5, KH = 6, GH = >10, NH4 = 0, NO2 = 0, NO3 = 0, temperature = room temp 20C
Tech specs: power head (5w) in the lower layers, small filter for water circulation in the upper layers, LED-60 RGB Light system, water tank = 30x30x35cm (31L)
The tank has about 1 inch (2,5cm) "rinsed" soil (seeding soil or tiger soil with one table spoon of bone meal) and 1 inch of fine (1-2mm) gravel on top. I filled the tank with many easy rapid growing plants. The tank is a "cocoon 3" (Cocoon 3 + LED 60 - Aquatic Nature), but I think the lighting is to weak? Not sure how much PAR, lumen, etc. I have in the tanks.

Should I buy this lamp? Chihiros WRGB II LED..

Water Plant Vertebrate Organism Pet supply

Plant Light Rectangle Vegetation Terrestrial plant

Water Plant Light Pet supply Organism

Plant Water Organism Pet supply Aquatic plant

· Registered
50 Posts
Discussion Starter · #35 · (Edited)
To be honest (TBH), that's way more than I would ever pay for a light. But if it fits your budget, who am I to judge? In my experience, most of these LED lights are too intense for a tank where they will be on for over half a day (in order to incorporate a four-hour siesta), without much in the way of mechanical filtration and with enough fish poop to keep your plants growing. Too much intensity and they can become absolute algae factories.

So, sure. Personally, I'd buy something that either has a dimmer or is dimmable and a timer and with as close to 100% white lights as possible and leave it at that.
What about this one, its a cheaper LED (1400lm, 14W, 8000K, 400-700nm)

Rectangle Slope Font Parallel Pattern

· Registered
50 Posts
Discussion Starter · #41 ·
Have a look on C-series lamps - Chihiros C361 LED light with dimmer (18 W, 1850 lm) - chihiros aquatic studio - I have the slightly shorter version for a couple of years on my similar cube aquarium (half the water volume) and it is great. Works with cheap generic automatic sunrise/sunset dimmers, provides plenty of light (I am running it about 80% max) and is water resistant (unlike other Chihiros lights). Just be aware that it heats a lot (like many LED lights though), so don't use it in confined spaces with lack of air/heat exchange.
Yes, maybe that lamp will fit my cubic tank better (30x30x35cm) and give light to all areas of the tank? So, these chihiros lamps gives a lot of heat? The one I have now does not, but it is only 3,6W.

· Registered
50 Posts
Discussion Starter · #44 · (Edited)
A few days at 20C might be okay, but 20C for long periods would probably slow plant growth.
Yes, after growing the plants for less than a week in two different tanks, both with 20C or less, have supported the fact that very slow plant growth is observed. Not a surprise, with new established tanks, but as you say, the low temperature is not helping the plant growth. New heaters are ordered.

So, I read in another post that the "kick off" in a walstad tank is after two weeks and may last up to six weeks? Is this correct? Between 2-6 weeks the soil will start to release a lot of nutrition in form of NH3, NO2, CO2, etc? As for now, the water layer does not seem to contain anything of importance for the plants.

· Registered
50 Posts
Discussion Starter · #46 · (Edited)
Yes, I have a KH = 6 and GH = >10. what do you think about hang on filters in the start up phase, are they a no-go due to risk of too oxygenated water? Maybe internal filter will be more suitable to prevent too much oxygen in the water. I also have to buy some more plants with powerful root systems, as the ones I have now has less roots. These are the ones I have now (pretty much fast growing plants):

Nymphoides hydrophylla
Limnophila sessiliflora
Vallisneria spiralis
Pistia stratoides
Nymphaea lotus zenkeri
Hydrophylla polysperma
Vesicularia dubyana
Microsorum pteropus
Ceratopteris thalictroides
Hygrophila corymbosa
Cardamine lyrata

· Registered
50 Posts
Discussion Starter · #48 ·
No. It's more like 2-6 weeks for toxic gases in anaerobic areas to build up in the substrate and perhaps even before CO2 production from decaying organic matter in the soil begins to "kick in". The slow release of CO2 from organic matter in the soil is one of the main advantages the Walstad method affords low tech hobbyists like me to raising interesting plants without the standard CO2 dispensers, tanks and other devices.

The fact that you're not getting high readings of nitrogen by-products right now is probably a reflection of your mineralizing skills and very likely of the fact that your soil mix was very low in nutrients to begin with. Until you start getting some fish poop in there, you should probably start adding some flake fish food on a daily basis to supplement your plant's nutrients.
I do not have a method for reading CO2 levels in my tanks. Have you any experience with the JBL CO2 test?

I will test my tanks regularly for nitrogen bi-products, and if I am not detecting any, maybe I should start adding fish food as you say. Unless, I could add a minor dose of concentrated NH3, to get the tank cycled.
1 - 20 of 48 Posts