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Soil question for the Walstad tank

7287 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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O
mysiak said:
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.
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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.
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Oslo said:
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.
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I would say that majority (if not all) of higher powered LED lamps produce a lot of heat, but they should be constructed to handle this. Users just have to be aware not to cover them (so the heat doesn't accumulate) and that they need to be handled carefully when switched on.

I have similar low powered LED lamp too (came with the tank) and I used it for artemia hatching or mushrooms growing, for anything else it was just too weak (IMHO). :)
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Oslo said:
What about heaters, should I invest in some? I have only 20C in my flat. What is the optimal temperature for a walstad tank?
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A few days at 20C might be okay, but 20C for long periods would probably slow plant growth.
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O
dwalstad said:
A few days at 20C might be okay, but 20C for long periods would probably slow plant growth.
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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.
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D
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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O
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
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J
Oslo said:
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?
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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.
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johnwesley0 said:
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.
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I do not have a method for reading CO2 levels in my tanks. Have you any experience with the JBL CO2 test?

www.jbl.de

JBL CO2-pH Permanent Test

Permanent direct measurement of the perfect pH value and carbon dioxide content in the aquarium.
www.jbl.de www.jbl.de

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.
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Oslo said:
Unless, I could add a minor dose of concentrated NH3, to get the tank cycled.
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Don't worry about cycling your tank. You want plants. You want plants that will consume ammonia. Plants and so-called, "beneficial bacteria" compete with each other for ammonia. This is one of many, many take-aways from Diana's book.
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O
Did some new water tests yesterday evening.

NH4 = 0,4 mg/L
NO2 = 0,2 mg/L
NO3 = 1 mg/L
GB = 9
KH = 8
pH = 7,5
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Oslo said:
Did some new water tests yesterday evening.

NH4 = 0,4 mg/L
NO2 = 0,2 mg/L
NO3 = 1 mg/L
GB = 9
KH = 8
pH = 7,5
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So, your tank has "cycled" in the sense that beneficial bacteria are doing their work. If you're lucky, the nitrification process can continue at this rate indefinitely with only a slow buildup of NO3. What's likely to happen, however, is that the nitrate level will increase as more ammonia is absorbed by more bacteria. Rapidly growing plants at the substrate level help rob the bacteria of ammonia, thus slowing down the creation of nitrates.
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O
NH4 = < 0,05
NO2 = > 1
NO3 = 40-80

Seems like the tanks are about to be cycled soon...... Just have to wait for nitrobacter, nitrospina and nitrococcus to convert nitrites into nitrates before adding any fish in the tank. Did run a test on the ability of the tank to convert ammonia into nitrites also (by adding concentrated NH3). NH4 levels were rapidly converted into NO2 by nitrosomonas, nitrosospira, and nitrosococcus or stored/converted and used by the plants. Either way, ammonia and ammonium levels does seem to be under control now. High nitrite levels are not harmful for aquarium plants (as written in ecology of the planted aquarium) so I do not have to worry about water change before NO2 levels decrease and NO3 levels explode.
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J
Your tank has been cycled for a week now. Unfortunately, a nitrate level of 40-80 ppm is not good for fish. Let's take a look at what your tank looks like.
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O
johnwesley0 said:
Your tank has been cycled for a week now. Unfortunately, a nitrate level of 40-80 ppm is not good for fish. Let's take a look at what your tank looks like.
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Sure, I will take some photos later today after work.
Yes, I agree, too high nitrate level is not good for anything. I will do a water change to remove the high level of nitrate before I add fish. I read that nitrate levels between 5-20ppm is ok for plants and fish.

I will start to poke the bottom layer with a stick also to get rid of trapped air in the soil.
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O
Tank no 1

1x Hydrophylla polysperma
2x Ceratopteris thalictroides
1x Nymphoides "Taiwan" hydrophylla
2x Cryptocoryne wendtii "Green"
2x Echinodorus?
1x Hygrophila corymbosa?

So, the H. polysperma and the N. hydrophylla seem to grow. The Echinodorus, C. wendtii, H. corymbosa are status quo and the C. thalictroides may decay over time, we will see. I have reduced the light a bit even if I have not observed any major outbreak of algea yet. I have a hang on filter, heater and a power head in the tank. About 1 inch (2,5 cm soil and 1-1,2 inch (2,5-3 cm) cap with gravel 1-2 mm. The original Vallisneria spiralis and the Limnophila sessiliflora had to go as they "melted"/decayed. The hang on filter is used to speed up the cycling and ensure circulation in the upper water layer. Hopefully, I can remove it when the tank settles in.....


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O
Tank no 2

Have not done anything with this tank, except adding some floaters (pistia) since the startup with the aim of getting rid of ammonia/ammonium. L. sessiliflora and V. spiralis have not done so great in this tank either, but I have just let the tank be untouched. The L. sessiliflora gets some beating from the power head and many of the V. spiralis have melted (in the background of the tank). Hydrophylla polysperma seem to like the conditions also in this tank, not sure about the other ones yet. I have a Eiheim Mini Flat internal filter, power head, and heater in this tank for now.

Limnophila sessiliflora
Vallisneria spiralis
Pistia stratoides
Nymphaea lotus zenkeri
Hygrophila corymbosa
Hydrophylla polysperma
Cardamine lyrata
Microsorum pteropus


Plant Terrestrial plant Grass Leaf vegetable Flowering plant

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J
These are very attractive tanks. You can probably add fish at any time and only have to make partial water changes every few weeks. Frankly, I was surprised by how quickly the nitrates spiked in that tank where it hit between 40-80 ppm. Or were you describing both tanks?

I think your emphasis on the traditional cycling process was perhaps a tad misguided, but it's fairly common for Walstad beginners to do so. I know I did in the beginning.
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O
johnwesley0 said:
These are very attractive tanks. You can probably add fish at any time and only have to make partial water changes every few weeks. Frankly, I was surprised by how quickly the nitrates spiked in that tank where it hit between 40-80 ppm. Or were you describing both tanks?

I think your emphasis on the traditional cycling process was perhaps a tad misguided, but it's fairly common for Walstad beginners to do so. I know I did in the beginning.
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My water test results published above represents tank 1, tank 2 still have some ammonium present (at least it had ammonium two days ago). Both tanks have high nitrite levels, which is toxic for fish. I will add fish when I am sure the nitrite levels are close to zero. I am not sure frequent water changes will speed up the nitrite to nitrate conversion as I am dependent upon the build up of beneficial bacteria. Maybe it is "best" to just let nature take its time and do water tests a couple of times a week to monitor the nitrite levels and hope they decrease in the nearby future.
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Oslo said:
Maybe it is "best" to just let nature take its time and do water tests a couple of times a week to monitor the nitrite levels and hope they decrease in the nearby future.
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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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D
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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