# Thought I'd improve the Walstad method - I was wrong!



## GAM (Jun 13, 2019)

Hi folks,

I own the first edition of Ms. Walstad's superbly written book, Ecology of the Planted Aquarium, but thought I could improve the "El Natural" method by combining high and low tech. How wrong I was - I've experienced mostly stunted plant growth:

Instead of using plain gravel and soil, this is what I did when setting up the 29 gallon tank:
a) The bottom layer is about 1/4 of an inch of of the previous aquarium substrate (where vallisnerias where once thriving): gravel and crushed coral blend.
b) On top of that I placed a bunch of plant fertilizer tabs as well as aquariumplants.com Iron and Trace substrate pellets, maybe one 1.5" apart from the other.
c) On top of that I put at about 1.5" of Espoma Organic Potting Mix.
d) Around it (a border to hide the soil from view) and on top of it is a bag of Flourite Black Sand; I chose sand because I wanted to keep the soil from going all over the place and staining the water too much, as my past effort when I used plain gravel.
e) On the very top of it all is a bag or two of Carib Sea Eco Complete Planted Black Aquarium Substrate.

The total substrate's depth is about 2 - 3 1/4" (sloping).

Except for the Water lettuce (which I don't remove often enough - there may be part of the problem as it shades the other plants*), the growth is surprisingly stunted.

The tank is filtered by a Fluval 50, has a heater, and currently supports guppies as well as Java Fern, Christmas Moss, Sagittaria subulata, Crypt wendtii, and Echinodorus xinguensis. I had other plants but they were over-shaded by the Water Lettuce and perished when I went away for a few weeks (a relative fed the fish).

I don't know what is going on, but I thought that the dynamics here of the interaction between the soil and the Flourite/Eco Complete substrate would interest the more science oriented folks among you. - I had used the same tank with less light output and just plain topsoil and washed gravel years before, and the results had been amazing (except for the filter getting clogged with soil and the water being more stained)! The only other difference had been my use of a larger canister filter. _It seems to me that the plants that depend on their roots for nutrition are doing poorly_; Water Sprite was the only other plant that was thriving - until it was overshaded by the Water Lettuce.

Any advice? I've been back for a couple of months now, and the Water Lettuce is the only plant that seems to be thriving; everything else is just... hanging on by a thread, except for the Jungle Vallisneria, which is growing at a slow pace.

Thanks!

John

*PS. In my previous attempt at El Natural, when plant growth had exploded, I was unable to keep the Water lettuce alive; I now think that they were kept in too high humidity, as I didn't leave enough space between the leaves and the aquarium's glass lid.


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## hoppycalif (Apr 7, 2005)

Welcome to APC! I suggest that you just follow the Walstad book instructions, until you have accumulated enough experience to understand why it works so well. Then you might be able to identify an "improvement" that really is an improvement. The advantage of doing it this way is that a lot less work and risk is involved. I plan to follow this path when I restart my aquarium after moving to a different housing situation. So far I haven't tried the El Natural method.


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## dwalstad (Apr 14, 2006)

GAM said:


> In my previous attempt at El Natural, when plant growth had exploded, I was unable to keep the Water lettuce alive; I now think that they were kept in too high humidity, as I didn't leave enough space between the leaves and the aquarium's glass lid.


I've had a floating plant problem for years but never did anything about it. This year, I started adding a small dose of micronutrient fertilizers (iron, copper, EDTA) to the tanks every month. The response from floating plants (Frogbit, Water Lettuce, duckweed) has been fantastic! Also, the fertilization turned around some Water Wisteria that was getting ready to die.

I believe the rooted plants in the tank, which can get their micronutrients from the soil, also draw on micronutrients from the water and starve out the floating plants.

I may add a _tiny_ revision about this to the next printing of my book. Thanks for your comments.


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## fpn (Jan 2, 2019)

Capping soil with eco-complete is not necessarily bad, some people do swear by it.

The added sand could be an issue if the cap is too dense / thick. That could be somewhat fixed by planting plants with good root structure and poking the substrate regularly with e.g. a chop sticks to aerate the substrate.

The thing that sticks out to me are root tabs / substrate pellets every 1 1/2 in seems suspect to me.

For comparison the Seachem root tabs can provide root fertilization for 72 square inch each tab.

Also potting soil is a little acidic, my guess is that the soil is dissolving the root tabs / iron substrate pellets and you get metal toxicity which kills your roots.

What do your roots look like?

Also if you have an iron test and you poke your substrate (maybe w/o fish) and then measure that may give a hint.

Last, do you inject CO2 ? Just curious - because soiled tanks are pretty common in high tech.


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## Am2020 (Sep 10, 2019)

My guess is that the substrate is not getting any oxygen and causing toxic levels to accumulate. Try adding Malaysian trumpet snails, cories, and loaches to help stir the top layers. Large plants with strong roots can actually transport oxygen to the lower layers. Helping to improve the substrate for other plants to root into. There also might be too much fertilizers and its burning the roots or at least preventing them from growing. Or maybe the pH is too low underneath the substrate layers.


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## Michael (Jul 20, 2010)

Re fluorite cap over soil, I have used the coarse red-brown fluorite in a typical Walstad set-up with no problems. (Except I don't like the way it looks, lol.) Others have reported using Eco Complete over soil with good results. So I don't think that either of those materials is the cause of your problems.

My guesses are excess depth of substrate, too much fertility from root tabs etc., and the very rich almost 100% organic matter "soil". Too much of several good things.


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