"Dirted" Tank

Stonesy

I'm very interested in this subject. I've never heard of this form of substrate before. Miracle Grow is safe? Is it because it's sterilized? And I was discouraged when I wanted to use sand, told by the LFS that it would ruin my filter mechanics. At some point I'll be moving and would like to have knowledge of this, sounds great for the well planted tank. I do have a well planted tank...two of them and both are doing fabulous. I just like the idea of plants in a soil. The fertilizer for plants is OK for fish? Just curious, for now.

Byron

I've kept out of this thread because the OP asked specifics and other members have experience and could better respond. But now that you have asked specifically, I am going to mention a couple issues with this method so you can best decide for yourself. Soil is without question the more involved type of substrate and there are risks that do not come with other substrates.

First consideration is fish; any fish that actively digs in the substrate is not advisable in a tank with a soil substrate. The muddy water will not hurt the fish, but it will be unsightly and constantly so. Small substrate fish like corys are usually OK with a sand overlay as they generally do not dig deep enough, but loaches and larger catfish will. My loaches and pleco tunnel and this would be disastrous with soil.



Soil can cause water quality issues. Most acknowledged planted tank sources using soil recommend running the tank for a few months with no fish to allow things to fully stabilize. Diana Walstad, a microbiologist and one of the principal proponents of using soil, mentions these issues [taken from her article in TFH, November 2009]:

• soil can becomes anaerobic much faster than a pure gravel substrate, inhibiting plant growth and producing toxic compounds to fish;
• soils will pull oxygen out of the water especially during the first 2-8 weeks;
• the initial soil chaos will flood the water with nutrients that can stimulate algal growth, and this can inhibit plant growth, creating a vicious cycle, killing plants and making the soil even more anaerobic.

You asked about plant fertilizers being safe for fish, by which I assume you are referring to any fertilizer in the packaged soil: Diana recommends an organic potting soil as the best soil; inorganic soils may contain chemical fertilizers which will do even more harm. Soil depth should be no more than one inch. The gravel top layer should be an inch; sand less than an inch in depth. These are added after the plants are planted.

Nutrients are cited by most soil-substrate advocates as the benefit, but this is a bit misleading. Initially depending upon the makeup of the soil there will be nutrients, and the organic matter in it will produce more CO2 than in a newly-setup tank with just sand or gravel. Down the road there is no benefit to soil; nutrients will become exhausted just as they do in your garden. And CO2 production will occur from organics in the substrate no matter what it is comprised of, which is why we don't clean it. Nutrients in the aquarium as in nature only come from the water. The water percolates through the substrate bringing nutrients. Any substrate will achieve this. Your existing planted tanks are doing so, or they wouldn't be "fabulous." As are mine, check the photos under "Aquariums" below my name on the left.

There are many methods to set up a planted tank, and all of them will work. Some carry more issues than others, and they largely depend upon what the aquarist wants for the end result. It is your decision, but in your case from what you have written, I would venture to say you would see no benefit, but may see quite the opposite.

Byron.

PonyMan

>>I've kept out of this thread because the OP asked specifics and other members have experience and could better respond.<<

No, no Byron. By all means pipe in! This is what I was looking for..."other" opinions about the subject. I should have maybe been a little more specific.

>>Down the road there is no benefit to soil; nutrients will become exhausted just as they do in your garden.<<

This makes perfect sense to me. Just like a potted plant on your kitchen table. Sooner or later the soil its' in will run dry of its' nutrients. I don't want to have to go back and "re-dirt" for sure, not even 10yrs down the road!

Can you explain how, I mean exactly how, your best planted tank is set up Byron? Substrate type, depth etc? I'm wanting to set the 55G up planted, just a nicely planted soothing tank to relax and enjoy viewing. I could achieve this with plastic plants etc but am really interested in the beneficial factors of live plants.

Steve

Stonesy

Thank you Byron, I agree with you. I would not benefit from delving into a soil substrate! at any time, I think it's a very interestig subject, a little over my experience level though.

Stonesy

Byron

In my 20 years I have I think tried/used all substrate types except for soil. I've had gravel-only tanks, gravel with a layer of laterite under it, sand-only tanks, and an enriched substrate (Seachem's Flourite). I supposed another I've never used is kitty litter, but when that fad came in I could not see any benefit, and few if any now recommend this so I assume it was not much to write home about.

If you've viewed my tank photos you'll probably agree that the plants look healthy in all of them. There are 3 different substrates among those. The 115g, 33g and 10g are playsand, the 20g and 90g are fine gravel [one specifically is slightly calcareous], and the 70g is Flourite. There are some identical plant species within all of these, namely Echinodorus (swords) and/or Hellanthium (pygmy chain swords, two species) that are substrate rooted. And light is identical spectrum. So this provides a reasonably good criteria for observing the difference due to substrate. And frankly, I see none.

I have a major issue aside from this, and that is my water. It is very soft, out of the tap the GH and KH are probably zero or at most less than 1 d. This is causing me issues with calcium deficiency primarily, but also magnesium and potassium deficiencies. These nutrients are included in Flourish and Flourite and Flourish Tabs, but minimally because Seachem naturally assume most users will have medium hard water which contains sufficient calcium and magnesium, and maybe some potassium. I mention this because this is the only major growth issue and it is fairly recent [I won't go into the details of how I was solving it, or am doing now].

The gravel substrate is 3 inches depth overall. The sand is 1.5 inches in the 33g, and 2 inches in the 115g, built up a bit in the back for the larger swords. From setup I use Flourish Comprehensive liquid once a week. And fish go in on day one so there is some initial CO2 and more as the organics accumulate in the substrate over the first weeks. I don't touch the substrates. I have Flourish Tabs next to the large swords in the 90g and 115g and they have helped, in addition to once a week dose of Flourish Comprehensive. The same swords and esp pygmy chain in the 70g with Flourite substrate are showing identical calcium and potassium deficiencies as in the other tanks, so this is not substrate-related.

Light is the most critical factor, and as I firmly believe in minimal lighting for the sake of the fish, I have plants that manage under that. Less light means less nutrients required.

I hope I've managed to respond to your question, but feel free to ask further.

Byron.

Mikaila31

My soil tanks have never had any more issues then a regular planted tank. Anaerobic soil happens, I've never had issues with it being there other then slightly hindered plant growth. My one soil/sand tank has some issues but I sure those never would of happened if I hadn't moved the tank and disrupted its established balance. I guess it makes up for the tank being basically algae free till it was over a year old.

I've never used a bagged soil though so I have no idea how that relates.

This was my first soil tank, which did amazing until I moved it. The move disrupted its balance a lot(same with my non-soil tanks, but worse in this one). Its finally recovering and some plants did not make the switch. It was fishless for a couple months due to its issues the fish were having, shrimp were fine. A lonely 6 week old rainbow fry has been living in it for 2-3 weeks and is growing fast.

PonyMan

>> I've had gravel-only tanks, gravel with a layer of laterite under it, sand-only tanks, and an enriched substrate (Seachem's Flourite). <<


So out of the gravel and the sand which would you say is better IYO Byron, if one can indeed be better than the other?


P.S. I have to say, this is a great forum! There are MANY out there that there's no participation and they are just simply dead. I have always been a "forum oriented" guy when it comes to any of my interests (and man do I have some varied interests! LOL). There is so much to be learned from others all over the world through forums like these! Thanks again for allowing me to be a part of this one! :)

Steve

AbbeysDad

At the risk of disqualifying this (my) post, I must admit that I do not have a soil ('dirt') substrate tank.
However, I have studied it some. Oh, and I have managed a 3000 sq. ft. organic garden for many years and made tons of compost and vermicompost (composting with redworms).
I think some of the comments that have been made are not quite accurate.

Growing plants in sterile sand using chemical fertilizer seems quite like hydroponics to me while the sand capped soil substrate seems more like an organic (biotope like) approach. I'd also challenge that the natural substrates of most streams, lakes, ponds, ditches etc. are more often soil and muck, rather than sand based.
Decaying plant and fish waste along with uneaten food break down in the upper substrate layers to feed the soil which feeds plants.

I think the real secret to success with a soil substrate in a fish tank is to have organic topsoil where the organic material is fully decomposed as you really don't want decomposition deep in the substrate. Mineralized top soil has been used very successfully.

Depth is another contention I have. Many suggest 1" of soil and 1" of sand (give or take). I can't imagine growing plants in 2" of "soil". A total depth of 4"+ (give or take) would seem more appropriate.
Dustin of FishtankTV has very deep soil substrates, but his focus is plants more than fish.

AD

Byron

You are quite right; there are a great many knowledgeable aquarists on this site. And while we may differ on our methods, we do so from the basis of our individual experience and research. And that is of great value to all of us.

To your question, the answer to which takes some thought, since it depends upon what you or I might mean by "better."

With respect to the plants, they will grow healthy and well in either sand or fine gravel. Provided the light is sufficient (intensity and duration) and balanced with the 17 necessary nutrients in the water column. [On this point I respectfully disagree with Ms. Walstad, who has more than once written that you cannot have a successful planted tank with plain gravel or sand; my 20-year experience and that of many others certainly contradicts this.]

With respect to fish--and I always put the fish first, my plants are secondary--some substrate fish will be better off with sand. There are upper fish that are substrate sifters in feeding, and sand would be more natural for these too.

Then there is the biology of the aquarium. And here there are some important issues. Large gravel such as true pea gravel is not recommended for planted tanks. Some plants do have difficult anchoring in this [I tried it once]. More importantly, the large size means that water will flow through it too quickly, removing nutrients from the roots. Bacteria also have a more difficult time. Fine gravel (1-2 mm grain) is said by many sources to be the best planted tank substrate. The issue usually mentioned with respect to sand is compaction. But this is not a bad thing provided it is not widespread. You can read more on this here:
Bacteria in the Freshwater Aquarium

I have switched 3 of my tanks, and intend to do a fourth next month, from gravel to playsand. I guess that says which I prefer.

Byron.

Byron

A quick comment on AD's mention of substrates in the natural habitats. The majority of streams in Amazonia have a sand substrate. There are some with gravel and rock, and some with solid rock. Few contain any aquatic plants. But even those that do, such as the Rio Negro, is sand, which can be replicated with playsand.

The plants we use in our aquaria that I refer to as substrate-rooted are often amphibious bog plants. These grow emersed half the year on the forest floor, which I understand is often thick clay or sand or a mix. I believe soil or dirt as we are using it here does not occur in any appreciable quantity, if at all. The organics are very prevalent from decaying plant and animal life, and in that environment breaks down rapidly and provides the nutrients to sustain the entire forest. The crypts in SE Asia grow in iron-rich clay. Vallisneria is a true aquatic plant, and it grows abundantly in the sand substrate in Lake Malawi.

Trying too closely to replicate a natural habitat with respect to substrate can be more trouble than good. Sometimes we have to make compromises to preserve the biological stability.