# Could soil based tanks go without ever replacing soil?



## kidgrave (Feb 4, 2014)

Let's say I setup a high tech tank, and with about 70 par, will I get away without ferts for 2-3 years? 

My other question is, why do people use fertilizers in a high tech soil based tank? I know that soil has high CEC, so does dosing ferts in this setup make it so that the soil gets recharged with the nutrients, and so that the soil lasts even longer? I've been wondering about the soil being able to absorb the dosed nutrients, because if it is possible, then the soil could be on the tank without ever needing replacement.


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## Absntmind (Jul 16, 2012)

No, the soil will eventually become dirt as the nutrients are used up. One can add tabs and such to continue using the soil without replacing it. Soil will not absorb nutrients in the water column. Aquatic plants also absorb nutrients from the water column, not just their roots. That is the reason for dosing in a dirted tank, along with dosing for plants which feed primarily from the column.


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## kidgrave (Feb 4, 2014)

Absntmind said:


> No, the soil will eventually become dirt as the nutrients are used up. One can add tabs and such to continue using the soil without replacing it. Soil will not absorb nutrients in the water column. Aquatic plants also absorb nutrients from the water column, not just their roots. That is the reason for dosing in a dirted tank, along with dosing for plants which feed primarily from the column.


After seeing Glossostigma Elatinoides growing in nature, while visiting Australia, it didn't make sense to me why the soil will need replacement. I have been confused because soil doesn't need to be replaced in nature. Why do people dose ferts when the soil still has nutrients? Wouldn't it be better if people wait for the soil to start running out of nutrients, and then worry about dosing?


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## GraphicGr8s (Apr 4, 2011)

In nature nutrients are replaced. There is an entire ecosystem in place we can not duplicate. Plants die and breakdown. We stop that in our tanks. There is a greater surface area and a more diverse atmosphere and water/air interchange where nutrients can exchange which we lack. Soil gets "spent" The nutrients get used up and really can't be replenished by "nature". 
Some nutrients are also only available to plants in a certain form or when the ph of the soil is at a certain point. Sometimes the nutrients are "locked up".


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## Absntmind (Jul 16, 2012)

GraphicGr8s said it better than I could. With a tank you are creating a sealed environment with limited resources, so we have to basically make up the difference for what would happen in nature. Yet even in nature events can happen over time which cause soil to stop being replenished and looses all it's nutrients. That is when it becomes dirt and nothing will grow from it.


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## Sparklescale (Nov 22, 2013)

If the tank is kept spotless and all plant debris and fish waste and food are siphoned out on a regular basis, then, there is nothing to replenish the nutrients in the soil except by adding fertilizers. Also, fast plant growth in higher light setups will use up nutrients in the soil faster than they can be replaced by the decomposition of plant mulm and fish wastes if it is left in, anyway. Low light soil bottom tanks planted with slow growing rooted plants, and, a moderate fish load can last for years without added fertilizers or CO2 ... see Diana Walstead's "The Ecology of the Planted Aquarium". She has tanks that have been running for years with the same soil substrate with fish food being the only additives to feed the plants, so, it is possible to keep the same substrate healthy and productive for years. Going high tech/high light however, will probably require soil fertilizing on a regular basis to keep it going long term.


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## lamiskool (Jul 1, 2011)

GraphicGr8s said:


> In nature nutrients are replaced. There is an entire ecosystem in place we can not duplicate. Plants die and breakdown. We stop that in our tanks. There is a greater surface area and a more diverse atmosphere and water/air interchange where nutrients can exchange which we lack. Soil gets "spent" The nutrients get used up and really can't be replenished by "nature".
> Some nutrients are also only available to plants in a certain form or when the ph of the soil is at a certain point. Sometimes the nutrients are "locked up".


exactly this, nature has its own systems of insects/bacteria/fungus/worms/im sure theres other things that break down matter and recharge "soil" and in a sense create new soil in a balanced ecosystem. that it impossible to replicate in a traditional tank.

now if you want a tank that uses soil and you dont have to replace then go do this lol 

http://www.dailymail.co.uk/sciencetech/article-2267504/The-sealed-bottle-garden-thriving-40-years-fresh-air-water.html


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## Diana (Jan 14, 2010)

Also, in nature soil is being replaced as floods happen, and the old soil gets washed down the river and new soil takes its place. 

You are right that a soil with a high CEC will recharge with nutrients added as water column ferts. I found this out with Soil Master Select. I was dosing pretty well for a while, then other things got in the way and got pretty spotty about fertilizers (still fed the fish, though) and the plants did just fine with the fertilizers that had gotten trapped in the substrate.


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## talontsiawd (Oct 19, 2008)

There were some examples of tanks that have been going for 10+ years using MTS. If you google search mineralized topsoil, you find what nutrients run out and when. Plus, many supplement the MTS with a few additives to ensure they are in the substrate for long periods of time.

As for can it be done...after about 6 months to 2 years, you will probably notice a change in your plant growth. Many say the soil is all used up, depleted of nutrients, but all it means is that you need to start to dose fertilizers and/or add root tabs. If you want about 70 par at the bottom of your tank, you likely will have to supplement ferts anyway. 

I don't think any soil claims to last very long. Usually the advertise that it feeds up to 6 months, then you have to fertilize your plants, with it's everyday use. In a tank, I can only imagine everything leaches more quickly. My only point is, I would expect to start using some sort of supplementing after so period of time.


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## kidgrave (Feb 4, 2014)

Diana said:


> Also, in nature soil is being replaced as floods happen, and the old soil gets washed down the river and new soil takes its place.
> 
> You are right that a soil with a high CEC will recharge with nutrients added as water column ferts. I found this out with Soil Master Select. I was dosing pretty well for a while, then other things got in the way and got pretty spotty about fertilizers (still fed the fish, though) and the plants did just fine with the fertilizers that had gotten trapped in the substrate.


Is Soil Master Select some type of soil? Where you dosing once your substrate was running out of nutrients? For how long do you think it recharged your soil? When I was visiting Australia, I saw Glossostigma Elatinoides growing in nature, and I was told that the soil in the forest and creeks gets recharged because of decomposing matter, and also because the rain releases nutrients.

Bump:


talontsiawd said:


> There were some examples of tanks that have been going for 10+ years using MTS. If you google search mineralized topsoil, you find what nutrients run out and when. Plus, many supplement the MTS with a few additives to ensure they are in the substrate for long periods of time.
> 
> As for can it be done...after about 6 months to 2 years, you will probably notice a change in your plant growth. Many say the soil is all used up, depleted of nutrients, but all it means is that you need to start to dose fertilizers and/or add root tabs. If you want about 70 par at the bottom of your tank, you likely will have to supplement ferts anyway.
> 
> I don't think any soil claims to last very long. Usually the advertise that it feeds up to 6 months, then you have to fertilize your plants, with it's everyday use. In a tank, I can only imagine everything leaches more quickly. My only point is, I would expect to start using some sort of supplementing after so period of time.


Would you advise to start dosing ferts once my soil starts running out of nutrients? Some people have suggested to dose ferts, even though my soil hasn't ran out of nutrients, yet, but I am worried that could cause algae issues. I get about 45-48 par with the Finnex LED lights that I am using, and so far there have been no plant defficiencies with me not dosing ferts.


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## Diana (Jan 14, 2010)

Soil Master Select is a montmorillonite clay that is no longer being packaged under that name. Nearest equivalent is Turface, Safe-T-Sorb and Oil Dri. 

Fish food, and even the dust that falls in the tank are all fertilizers, but low levels. 
Water changes provide certain minerals. 

A substrate is sort of like your dinner plate. To eat, you gotta put food on the plate. But when you are done you do not throw away the plate. You add more food. 
Same with substrate. Fish food and other sources of fertilizer may be enough in a low tech tank, but are not enough in a high tech tank. There is nothing wrong with the substrate, it is simply an 'empty plate' and needs more fertilizer to be added to the system.


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## kidgrave (Feb 4, 2014)

Diana said:


> Soil Master Select is a montmorillonite clay that is no longer being packaged under that name. Nearest equivalent is Turface, Safe-T-Sorb and Oil Dri.
> 
> Fish food, and even the dust that falls in the tank are all fertilizers, but low levels.
> Water changes provide certain minerals.
> ...


In my dirted tank, would you advise that I start dosing ferts once the soil starts running out of nutrients, or before it runs out? Sorry for my late reply.


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## talontsiawd (Oct 19, 2008)

kidgrave said:


> In my dirted tank, would you advise that I start dosing ferts once the soil starts running out of nutrients, or before it runs out? Sorry for my late reply.


In my experience, in a low tech tank, you can usually get away without it. However, plants feed from both the roots and the water column, some do one more than the other, most benefit from both. However, many dose around what they need on high tech tanks in low tech, I find that about 1/10 of that is needed. 

I found that Flourish Compressive was about all I needed in a dirted tank, be it before or after it ran out. I usually recommend dry ferts but when you are dosing so little, I think just the Comprehensive does the trick.


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## Diana (Jan 14, 2010)

Depends on the soil. If you have a soil that starts off with some ferts, then I would go slow about adding more. Some of the bagged soils are like this. Trace amounts of worm castings and so on provide enough nutrients to get the plants and bacteria going. 

If your substrate starts with none, then start adding them right away. The Safe-T-Sorb sorts of products are like this.


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## plantbrain (Dec 15, 2003)

kidgrave said:


> Let's say I setup a high tech tank, and with about 70 par, will I get away without ferts for 2-3 years?
> 
> My other question is, why do people use fertilizers in a high tech soil based tank? I know that soil has high CEC, so does dosing ferts in this setup make it so that the soil gets recharged with the nutrients, and so that the soil lasts even longer? I've been wondering about the soil being able to absorb the dosed nutrients, because if it is possible, then the soil could be on the tank without ever needing replacement.


Works for some nutrients, but not all(Nitrogen is the biggest problem), and many plants are not planted into the soil. 

If you drop down to say 40-50 umols/sec of light, then have a good sized fish load, decent filter/wet/dry etc, then perhaps. But you need to feed the fish well.

And some plant species will do much better in such tanks, whereas others might not. 

It's not THAT hard t dose ferts if you dose the fish food after all, is it?
Plants take up from both locations and if you add ferts to the water, then you also prolong the life of the sediment.

No good reason NOT to dose ferts to the water column as well.

I have ADA AS in my 180 from 2008 or so, no issues. Some spots are mushing out to dust, but still grows plants just the same, it's basically rice paddie soil, clay loam that was enriched with NH3. NH4 is gone after about 3-9 months I'd say, bacteria and plant uptake, leaching etc, water change export etc.

The other ferts should last for a decade I'd suspect. 
Rice farmers rarely add much other than NH3 to their fields around here and where I live, we grow more rice than all of the Japan. The rice field soil is remarkably similar to the ADA AS in terms of nutrients and content. Hard pressed ADA soil works better, cleaner, less mess than the raw stuff from the field though. I prefer that vs the rice paddie soil, but they grow plants the same pretty much.


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## kidgrave (Feb 4, 2014)

plantbrain said:


> Works for some nutrients, but not all(Nitrogen is the biggest problem), and many plants are not planted into the soil.
> 
> If you drop down to say 40-50 umols/sec of light, then have a good sized fish load, decent filter/wet/dry etc, then perhaps. But you need to feed the fish well.
> 
> ...


Thanks a lot for your reply. I want to make sure that I understood what you said. Basically, the more par my lights give to my tank and the more plants I have and biological load, the more fish I am able to have, which would be able to provide more Nitrates into the water? 

I have a question that is not related to soil. I am getting tired of dosing excel in my tank, which gets about 45 par at the substrate with the Finnex Led lights I am getting. My Ph is at 7.6 and my Kh is at 14. Once I get my drop checker and have it running with pressurized co2, my ph should drop to 7.2 once I get about 30 ppm of co2, right?

Thanks :smile:


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## plantbrain (Dec 15, 2003)

No, the lower PAR means less demand from the plants= less nutrient demand.

So sources solely from say the sediment and fish waste are more likely to provide enough for the plants to do well.

If you add MORE light, then you are asking for MORE management, more CO2/nutrients etc.

If you have Anubias on wood, or Vals planted in the soil, or if you have say L. pantanal, they will respond differently. L. pantanal will be pickier than the Vals, and Anubias might not do so well on wood if you do not dose anything. Biomass of the plants also plays a role, as does Temp, cooler temps= less management etc.

And so on.

Non CO2 tanks does this the best, but plant choices are more limiting and gardening is not as intensive/as easy for most.


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## kidgrave (Feb 4, 2014)

plantbrain said:


> No, the lower PAR means less demand from the plants= less nutrient demand.
> 
> So sources solely from say the sediment and fish waste are more likely to provide enough for the plants to do well.
> 
> ...


Thanks for your responses. It's been about 2 months and a half since I set up my 10 gallon tank with soil substrate. I have my Finnex Led which is giving me about 45 par on the substrate. So far, I am growing stuff like Ludwigia Repens, Java Fern Tropica, Anubia Nana Petite, Eleocharis Parvula, and Christmas moss. I haven't dosed any ferts and so far I have been getting away with it. I agree with the point you made. I guess everything is about finding a balance, and I'm just gonna start dosing dry ferts to avoid any problems. 

I have a question relating to co2. I have a Ph of 7.6 and a kh of 14. Suppose that I setup a low tech tank, with about 25-30 par at the substrate and that the plant mass in my tank is high, and that I have about 10 ppm of co2 in the tank, do you think I would be able to get away without dosing co2? I want to understand a little more how plant mass plays a role in the tank. Thanks for your responses.


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