What is "el Natural?" A Step by Step?

John N.,

Diana Walstad is the originator of this idea and wrote the book, "The Ecology of the Planted Aquarium" so she's the expert, but I'll give you a concise preview:

1-1.5" of unfertilized (generic works best) potting soil
1-1.5" of gravel on top

Use at least 1.5Watts/gal of lighting PLUS some natural sunlight from a window.

Allow some plants to grow emergent or have floating plants like duckweed, salvinia, water lettuce. This keeps algae in check by giving some plants exposure to air (and thus CO2).

No fertilizers, CO2 or other additives are needed. The soil provides a myriad of beneficial bacteria, nutrients, minerals that keep the substrate from producing toxic gas like H2S etc. The plants get all nutrition from the soil and generous feeding of the fish. CO2 is provided by decomposition in the soil.

Others can probably give a better explanation, but this is a start for you. I can attest to the success of this method. I have the tank I've always wanted (lush jungle!) with no expensive products or heavy maintenance, and best of all---no algae problems. I'll attach a photo of it taken in its jungle incarnation.

EDIT: I see I left out two issues you asked about. Water changes are rarely needed. Every few months maybe. I've read of some doing only 2 a year! Filters are not neccessary since the plants filter the ammonia and nitrite out of the water, but you can use them for water movement and mechanical filtration---if you want. I think Diana suggests powerheads only for larger tanks. I have no filter in my little one gallon, and I use the Hagen mini submersable in my 10g for water circulation.

By "Generic Potting Soil", I think "Simple Potting Soil" could be used as well. Some commerical potting soils will change during their production year, as different products become seasonably available.

A Simple potting soil would have a moderate amount of composted organic matter (humus, leaf mould, etc) with some not-yet broken down material (peat, some tiny bark pieces, etc) and some inorganic material (sand, clay, tiny stones).

Its easier to mention what is NOT recommended. Because these ingredients add cost for the manufacturer, generally they're found in "name brand" potting soils.

Fertilizer - Miracle-Gro brand includes a slow-release fertilizer in their potting soil, intended to feed container plants, window boxes and such for the summer (about 3 months). This amount of nutrients will wreak havoc on your tank parameters, and probably result in an algae mess.

Perlite - while not a bad thing for houseplant soil, this stuff "lightens" heavy soils, especially those that tend to be high in clay. It provides porosity and helps to allow container plants' roots access to air from the small spaces between particles (very important for terrestrials). For the aquarium keeper, this stuff floats, and is a royal pain in the @$$, as the little white bits will float up for months and cling to anything in the water surface.

Vermiculite - also generally a good ingredient in houseplant soil, this is a mineral that has been expanded by exposing it to great heat. While it also "lightens" soils to some extent, it also provides a lot of surface area for water to cling to, and helps absorb and retain water, while not staying thoroughly WET. It evens out the wet/dry cycle. For the aquarium keeper, this isn't as annoying a floating component as perlite, and may help against compaction. (*aside - I've actually added some vermiculite to a soil underlayer as an experiment, with very good results to date).

Wetting Agents. These are surfactants. I've personally had a very bad experience with these when trying to pot up some very rare terrestrial plant cuttings. My bad experience was with Martha Stewart's potting soil from KMart. Shredded sphagnum peat has an annoying habit of being difficult to wet once it gets very dry. It actually repels water to some extent. A wetting agent, or surfactant, gets the water to make contact with the other materials, and increases absorbability. But, it also increases the moisture retaining time. For me, this kept the precious cuttings too wet for too long, and caused rot. I'm not positive what the effect would be in an aquarium, but my sense is that it would not be good for the creature or plants. Plants have a very thin natural cuticle to protect them, and I'd guess this would not "play nicely" with that. Who knows what the long term effects on fish would be.


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*sorry had to break this up into two parts - it was doing something odd where it repeats the same line over and over*

anyhow.....

Take a look at some of the cheaper soils. Those tend to NOT have wetting agents, fertilizers or other questionable amendments. I've used "Hyponex" and "Jolly Gardener" but found the contents of both brands to vary widely depending on where the bag was purchased, and at what time of year. Try a small bag of a few different types. Anything you don't use in the aquarium would probably be fine for houseplants.

Here is a VERY general assessment technique: Moisten it, play with it. When moderately moist (like a wrung out sponge), a small handful should have a bit of give when you squeeze it in your fist. Now open your hand flat. Does it crumble apart? That indicates its high in sand. Does it stay compressed, like a hard lump? High in clay. Does it look shiny or slick, or very muddy? That indicates a lot of organics.

Ideally, it will fluff back out a little bit (like when baking a cake - touch the top to see if its done - it should sping back when lightly touched) as you've released the compression. It should generally keep its shape, perhaps fracturing in one or two places. If you push on it, it should then break apart rather easily.

Now smell it. It should not smell moldy or astringent or bitter. It should smell pleasantly earthy, and the smell should not be noticable unless you have your nose right up to it.

Now you can start a bottle test (be sure to have a control of just water) to see if there are any wild pH swings! *Grin*
-Jane

Jane,

Why might you think that miracle grow would cause algae, yet adding KNO3/KH2PO4/Traces to very high levels would not in a non carbon enriched tank?

What might that suggest about NH4 and NO3? Is it really excess nutrients?

How many types of NO3 transportors are there and how many NH4 transportors are there in plants?

Do a google search.

There are many types of NO3 uptake transporters and they each respond to different levels of substrate nutrient concentrations.
A plant can adapt well to many variables, they adapt and this also fits the observation/s.

NH4 can be added to verify this.

Soil that has been soaked well prior, boiled etc, is well oxidized. This removes most of the liable NH4. Slow decomposition of organic N into NH4 slowly releases NH4 at non algae spore germiniating levels.
Embedding NH4 into clay at low levels also does a similar thing but without bacteria, rather, the root hairs penetrate the clay.

Regards,
Tom Barr

My suggestion to avoid potting soils with an added fertilizer (especially for one's first foray into using soil underlayers) was based on the El Natural methodology - the ideal soil will have nutrients, but in moderation. Just as the addition of composted manure is also not advised, the additional fertilizer in supplemented potting soils is considered excessive for an El Natural setup. In this type of setup, fertilizers are not added straight to the water column, either - the addition of fishfood, and its degradation by bacteria provide the main source of macronutrients for the plants.

There were a few cases where folks used a fertilizer-enriched potting soil in an El Natural setup, and they had great difficulty with their tanks, many times greater than the "usual" problems encountered as an El Natural soil underlayer is "settling in".

If the parameters are changed, such as the addition of CO2 supplementation or water column fertilization is added, then Miracle Gro potting soil with fertilizers might be just the right thing. But that's a very different setup.

-Jane

Believe me, I wouldn't have kept 3-9 tanks for last 19 years if it was that time-consuming!

I tried to write my book on a High School level of biology and chemistry. It's not stuff you can skim, but it shouldn't be too hard to understand.

I've never tried burying fresh plant matter in substrate. It could help (provide CO2). But it could also cause wild decomposition in the soil, because it is so fresh. Fresh organic matter like plants is like Fast Food for bacteria. I would have chosen something less tasty for bacteria (composted organic matter, peat moss, etc), so that you don't set up massive decomposition and anaerobic conditions in the substrate.

It might be prudent to wait several weeks after your first addition to see what happens before you add anymore.

Let us know what happens. Interesting idea for revitalizing old substrates!



Let us know if you think it helps. Interesting idea.

Fast Food & CO2

That would be good bacteria and not bad bacteria, correct?

Bottom line to me is - will it make my Mollies sick?

I have cleared out 1/3 of my 10 gallon tank because I think the lush growth of my plants was causing crowding my Mollies and causing them stress.

I have been losing about 1 Molly a week in either one tank or the other.
I just lost a 2 inch gorgeous Black Lyretail Molly.
The other Mollies again look fine and so do the 4 new neons that I added.

I have been using the Daily Dosage Schedule with my Seachem products, but wanted to slowly incorporate some things I learned from your book.

Should I take the mulm out, let it dry and then put it beneath the substrate afterwards? I thought this stuff and excess fish food was good.

(It has been 20 years since High School.)

Hmm.....