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Discussion Starter · #1 ·
One of our members send me a PM with the following. He agreed to let me post the response here.

Hey Art, your substrate article is awesome! Just a couple of questions, when using humus and peat does laterite need to be added? Would pumice, etc. need to be added to recycle the nutrients or does that happen without it? How much would I need for a 36"x18" base?
Firstly, humus is scientifically defined as that which is developed over time by the decomposition of organics (this meaning that it comes from the remains of living things i.e., deceased animal or vegetable life). It is commonly used in gardening and can be found in most nursery stores.

Secondly, I am not a big proponent of using humus or other very rich additives like earthworm castings unless I'm growing plants emersed. There is just too much seapage into the water column in my experience. The use of peat, however, is good as it stays together better and decomposes slowly.

Thirdly, the use of pumice serves a couple of functions. It is inert so it won't change the chemical makeup of the substrate solution. In addition, it prevents compaction on a long-term basis. It also provides a home for colonies of beneficial microorganisms that are charged with nutrient recycling.

I do add a little laterite to my mix. It provides iron that becomes soluble due to the acid substrate solution.

As for the 36x18, that is the footprint of my 58g. I like to put an inch of this stuff on the bottom. I use the following recipe: 5 cups pumice to 1 cup peat. I also add .5 cup laterite, charcoal and (well washed) greensand. I think this gives me enough for a 10 gallon tank so you may need to multiply that accordingly.
 

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Art, that should work well and not cost much.

I do think that adding Turface vs pumice would be better unless you have high iron pumice?

The iron would better placed inside the porous grains where the root hairs can find thier way into and where it's a better place for reduction of Fe/Mn.

You can soak pumice in a nutrient broth, add laterite etc, but putting most of the nutrients inside each grain provides better storage over the long term, less replanting issues etc.

I add iron filings and found little difference between that and Laterite.
There are a number of Iron oxides, complexes etc you can try unless you have a good deal on the laterite.

Iron will buffer the reduction above the range of Sulfate reduction.

Regards,
Tom Barr
 

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Art,

You worry about humics, but not greensand? Greensand is much more likely to cause problems with leaching I would think...

I wish I could get ahold of some pumice sand. Where do you find yours? I don't even know where to start looking. Home Depot and Lowes don't have that here...
 

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Discussion Starter · #6 ·
Tom,

Interesting point about the broth technique. I understand people are doing that now with Zeolite.

Wheeler,

Green sand that is well washed will not leach nutrients quickly. At least it hasn't for me. As for pumice, look up your nearest orchid supply store. They carry it. Otherwise, look for bonsai stores.

Raul,

I purchased mine from Dallas Bonsai. I like the brand they carry. Akadama may be expensive as it is imported from Japan. Just like when I was carrying Aqua Soil. :D I am trying to find an economical substitute. Certainly the commercial substrates would work. Alternatively, look into large grain sand (inert).
 

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Art_Giacosa said:
Tom,

Wheeler,

Green sand that is well washed will not leach nutrients quickly. At least it hasn't for me. As for pumice, look up your nearest orchid supply store. They carry it. Otherwise, look for bonsai stores.

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So, what is it that you expect humics to leach? Many people think soils and the like to be too rich. I think it's garbage-- More likely too little cap over those materials.

Humics/organic matter by themselves will cause no problems. You just need to use them in moderation lest they acidify your substrate destructively.

Thanks for the tip on pumice.
 

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Discussion Starter · #8 ·
Hey John,

I think you're right. I don't have a problem with humics when used in moderation. How much would you recommend?
 

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Depends on the humics :) With peat, it's hard to use too much. It'll just get too messy with much more than a handfull per square foot or so. With the granulated humics, I'd say 1-2tbs per 10g would certainly get the job done.

I don't have any experience with Barley Straw nuggets, so I can't say about that, but I'd bet that it's more similar in efficacy or *punch* to the granulated humics. After all, barley straw is almost totally undecomposed.

I have to say that I'm sold on worm castings. 1/2 cup per 10g is ample and seems to be extremely potent, not as volatile as a Jobes spike or osmocote though. They don't have anywhere near the same quantity of macros as the inorganic fert pellets, so I'd say they're safer than not. Just be sure to cap it well-- 2-3 inches minimum cap or ~3-4 inches total substrate depth with the undecomposed items being at the bottom.

Erik Leung and I discussed bat guano as a possibility. It's got a consistency similar to peat but it's loaded with macros, humic acids, and traces. Depending on the source, you can manipulate the type of macros you get which is neat. The diet of the bat or sea bird determines this. This would be the ultimate soil type amendment for macro kick if you wanted to try something extreme 8) You would need very little to get the benefits. I'd start with 1/4-1/2 cup per 20g and bury it as deep as you can.
 

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1/2cup per 10gallons will do the trick for how long in your tanks?? This is what keeps me from using worm castings and the soil substrates, i dont have a clue how long it will be before i will have to dose the water column.
 

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Exactly, how long do all these last before your substrate is depleted? Is that why pumice is a good thing to have? Wheeler, would adding a little GreenSand be a good decision since it's loaded with trace elements? And would using a layer of zeolite over the mixture of humus, etc. be a good idea to hold extra nutrients?
 

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I think we're making too much of this:

First of all, soils etc, will not stop you from having to use water column ferts. It doesn't work that way especially in high light tanks. Second, soils are low in nitrogen, and sometimes PO4. You'll still have to find another way to get those delivered. Third, some plants prefer foliar uptake of nutrients (or so I've heard) or at least have preferences for whether roots or leaves take up specific nutrients.

The MAIN benefit of having a soil in the substrate is the CEC. That is its ability to bind nutrients for root uptake. They're bacterial playgrounds and restaurants all rolled into a neat sludge ;) The nutrient store is secondary and, in my opinion, they should be used in conjuction with a reliable long term micronutrient material, ie:eco-complete, turface, laterite, etc...

Raul-7,

I don't have any experience with greensand, but there is a nice breakdown of it here:

http://home.infinet.net/teban/jamie.htm

As for the zeolite, I think there are easier ways to skin that cat. If you have some laying around then throw in a couple handsful. Activated carbon would do as well, but it's really not neccessary.
 

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Art_Giacosa said:
...

As for the 36x18, that is the footprint of my 58g. I like to put an inch of this stuff on the bottom. I use the following recipe: 5 cups pumice to 1 cup peat. I also add .5 cup laterite, charcoal and (well washed) greensand. I think this gives me enough for a 10 gallon tank so you may need to multiply that accordingly.
What's the typical footprint of a 10 gallon tank? Over here in Singapore we usually state tank WxDxH, as we get many tank shapes and sizes at the shops.
 
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