# Summary of Key Differences: Walstad Method vs Father Fish Modification of the Walstad Method



## HPC (Jan 3, 2022)

I'm a newbie to planted tanks, and have spent the last 2 month researching how to set up a planted aquarium.

Two schools of thought have attracted me: the Walstad (W) method, and a later variant by the Father Fish (FF) youtube channel. The following is my personal understanding as a newbie.

FF has a video where he acknowledges Diana Walstad's book was a major influence on him, and he said he started off using the Walstad method. However, he subsequently modified it to the extent that I believe it presents conceptual differences.

A first key difference is that, on top of the soil, (W) uses 1" gravel versus (FF) uses 2" fine sand. The rationale is that, in (W), the thinner 1" layer of 2-3mm gravel does not effectively isolate the soil from the water - because of the greater porosity of tiny gaps between the 2-3mm gravel. Whereas, in (FF), the thicker 2" layer of fine sand has a comparatively greater ability to isolate the soil from the water.

(Note: in some countries, 2-3mm gravel is called "sand" which can confuse the discussion among different people. Hence, the sand used in the FF method would be the significantly finer sand akin to the size of minuscule granules, for example, found in children's play sand.)

*Consequences of using 2x thicker substrate and finer sand:*

(W) fish cannot be added for several weeks/months, whereas (FF) fish can, and should, be added immediately from Day-2 since the presence of fish is seen as a key component that aids in establishing a biological ecosystem. This ability to add fish from Day-2 is because the 2" sand layer, to a greater extent, hinders the soil-nutrients from leaching into the water, whereas (W) the use of 1" gravel of size 2-3mm means that the soil more readily leaches its nutrients into the water that could be detrimental to fish if these are added too soon.

The difference is in (W) 2-3mm gravel vs (FF) fine sand.

The other difference is (W) being a 1" layer, versus (FF) being a 2" layer.

(W) Because the water effectively comes into contact with the soil through the porosity of 1" layer of 2-3mm gravel, it is useful, before setting up the (W) tank, to pre-treat the soil (called "mineralisation") so that the soil does not have such an initial negative effect on the water. Whereas (FF), because the soil is sealed off to a greater extent due to the fine 2" sand layer, the soil layer can be fortified with a host of extra nutrients before it is laid down in the tank. In FF, the prior mineralisation process is not needed before the tank is set up.

Other than these differences, it appears to me that (W) and (FF) are mostly consistent on other issues, such as the prime importance of plants in establishing an ecosystem in the tank.

I'd be interested to hear comments on what I understand to be key differences between the (W) and (FF) approaches to substrates.

Disclaimer: the above is from my newbie research from the last 2 months, and neither (W) nor (FF) were aware that I would write this.


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## Michael (Jul 20, 2010)

Your comparison is very thoughtful. I am not very familiar with FF. I think you have two minor misconceptions about the Walstad method.

"(W) fish cannot be added for several weeks/months" Actually, Walstad herself often adds fish immediately after planting. Of course she knows what she is doing, LOL. She closely observes fish and plant health and is prepared take corrective action if needed.

"(W) Because the water effectively comes into contact with the soil through the porosity of 1" layer of 2-3mm gravel, it is useful, before setting up the (W) tank, to pre-treat the soil (called "mineralisation")" Walstad herself does not do this (see above). Pre-treatment of the soil is a safety measure when using artificial, highly fertile, highly organic, commercial potting "soils". Natural topsoil with its relatively low fertility and organic matter content does not need pre-treatment. I am one of the people who encourages pre-treatment of soil for two reasons. First, many beginners only have "hot" artificial mixes to work with. If you are inexperienced, this can cause problems. Second, I am lazy. I don't like to do water changes on short notice. I am willing to forego the initial explosive growth in a Walstad tank from natural CO2 and fertile soil to avoid the bucket brigade.

Thanks for starting this discussion! I look forward to following it.


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## mistergreen (Mar 3, 2007)

The idea behind the deep substrate is to cultivate anaerobic bacteria which break down nitrate. That's the main difference I think.


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## johnwesley0 (Feb 23, 2021)

mistergreen said:


> The idea behind the deep substrate is to cultivate anaerobic bacteria which break down nitrate. That's the main difference I think.


I think I've come across that hypothesis. The only caveat I have about it is whether sand has the requisite surface area to really cultivate such a colony of denitrifying bacteria? I'm still experimenting with Safe-T-Sorb and in fact have a half-inch floor of it _underneath_ the soil in my latest tank, just in case there is something to this whole idea. Stay tuned.


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## mistergreen (Mar 3, 2007)

johnwesley0 said:


> I think I've come across that hypothesis. The only caveat I have about it is whether sand has the requisite surface area to really cultivate such a colony of denitrifying bacteria? I'm still experimenting with Safe-T-Sorb and in fact have a half-inch floor of it _underneath_ the soil in my latest tank, just in case there is something to this whole idea. Stay tuned.


I think the sand surface area is enough. There are many practical examples of deep substrate tanks up and running.


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## johnwesley0 (Feb 23, 2021)

mistergreen said:


> I think the sand surface area is enough. There are many practical examples of deep substrate tanks up and running.


Aren't septic tanks just great big, deep substrate tanks?


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## maico996 (Nov 6, 2016)

johnwesley0 said:


> Aren't septic tanks just great big, deep substrate tanks?


Lol!! That may be true but would you want to plant one?? 😂😂😂


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## mistergreen (Mar 3, 2007)

Heh, I think it’s a spectrum, closer to a regular dirt tank than a septic tank.


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## YodelMogul (Oct 7, 2021)

A bit of a departure but i’d just like to mention my friends method who is an ‘old school‘ aquarist. Basically all he does is use pea gravel which is quite coarse, maybe 1”+ depending what you want to do. His plant selection is interesting but does not allow for much flexibility imo because of the lack of nutrients. Vallisneria, java moss and duckweed, that’s it. Obviously the moss grows fine in just water and the val from my understanding is a more primitive species of plant that 1) grows very quickly 2) grows well with just fish waste. I know he has a tank with some other species but i suspect some plants would need additional nutrients. No heaters, no filters and he works primarily with livebearing fish (swordtail, platy). In the winter here tanks can get down into the 60s and there arent many problems. 

This is how i started and i feel like fish can safely be added once the plants acclimate to their new tank. I decided to go with Walstad method eventually because i am more interested in plants than fish tbh


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