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Discussion Starter · #1 ·
Will be taking delivery of a 25 gallon extra tall next week. Part of my motivation in ordering this oddball size was that I knew I wanted to plant with dirt, so this would give me extra depth. Do forum members have any opinions about whether I should make the dirt layer a little deeper in such a tank? Any other special considerations?

An ongoing source of conffusion (for me) is how widely opinion seems to vary in this forum and elsewhere about whether the "dirt" should contain organic matter or not. And what about peat? It's organic, and (again) some say use it, others: "no". I find it doubly unclear when dirt advocates who say "don't use any peat", in their next sentence advocate using commercial potting mixes that contain peat.

Thanks very much!
Evan
 

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Hi Evan,

I share your confusion. I think the answer is, there are many ways to set up a successful soil-based tank. Below are my personal opinions based on my limited experience and lots of reading and talking with successful aquarists.

First suggestion, don't use more than about an inch of soil, even though your tank is deep. Thick layers of soil tend to become anaerobic, which can cause problems in the confined environment of an aquarium.

Second, don't use a cap that is too fine. Very small particles (like play sand) inhibit gas exchange between the soil and the water column. This also promotes anaerobic conditions. Many people do use pool filter sand, but in my opinion it is also too fine.

Last, the question of peat and other organic matter. My observation is that the more organic matter (including peat) in your soil mix, the less soil you should use. With a very high organic matter content, it helps to mix some porous coarse inert substrate with the soil. The point of this is to reduce anaerobic conditions.

You've probably read the sticky in the library about mineralized topsoil. From what I can tell, the point of the mineralization process is to accelerate decomposition of organics in the soil. This makes the soil more stable in the aquarium (i.e. less likely to become anaerobic). Other parts of the process (such as adding clay, potassium, and calcium) are intended to increase the nutrient holding capacity of the soil and to prevent quick depletion of certain nutrients.

All of this makes the process sound more difficult than it is. In truth, just don't go to extremes on anything, and your tank will probably be successful.

I hope other people with more experience will comment on this topic.

--Michael
 

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Another reason organics gets pro and con agruments is the release of tannins. Some folks don't mind or actually prefer it, while others are quite put off by it. And it can change tank to tank. I have two tanks using the exact same substrate (MGOC capped with blasting grit). One gets tea colored after a month and requires water changes. The other is relatively clear, and I have only changed it twice in the last 5 months.
 

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Discussion Starter · #4 ·
Thanks Michael and Mudboots. Any opinion on whether my extra-tall should have a thicker substrate?
 

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I'm full of opinions ;). While I dont think it necessarily SHOULD have a thicker substrate, I think that the extra height will certainly ALLOW for it, as you will be able to house heavier rooted plants that will get taller/larger. Of course, in that case you limit yourself on space. For example, a deeper substrate will make for a full sized Amazon sword perhaps, but it will fill the tank.

Hmmmmmmmmm. My thoughts are tending toward a deeper substrate in the back planted with perhaps some Cryptocoryne sps., the larger ones, but with thin leaves, like retrospiralis et cetera. That would give you plenty of root mass but not completely prohibit scaping. There's also a light green lily, maybe it's Nymphoides, that gets massive roots, and it makes a great backdrop because the lime green is easy to offset with the darker greens of most other plants (not to mention the textural contrast). Those types in the back corners and work your way into a focal point somewhere with a specimen of sorts.
 
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