Milan, please don't take this as me trying to personally dispute what you've said...nothing personal here at all, I just want to expand on a few issues and clarify some point I may have failed on earlier.
Milan said:
No matter how you layer your substrate with organic stuff, such as peat, you will not eliminate decomposition,
Couple of brief points, the reason for using a small amount of peat is precisely for the benefits of decomposition. Again it's only a few handfuls for a 75 gallon tank. I add peat whether using Eco-Complete, Flourite, or plain gravel. The peat helps establish a source of nutrients for the plants during the first couple of months before the substrate matures. The decomposition adds
CO2 to the root zone and supplies macro and micro nutrients for the brief first few months.
even if you put a steel plate on the top of it. That means methane bubbles coming out of it, or even worse, chunks of it venturing to the surface.
Maybe if you are describing a full inch or more layer of peat this could happen, again you should only use a handful of peat per 10 gallons of tank. Any gas bubbles coming from this type of substrate would be
CO2 and/or
O2. It should be noted that any methane produced in the substrate is converted to
CO2 by a process label oddly enough Methane Oxidation by methane-oxidizing bacteria. It should also be noted that 91% of the methane produced in the Florida Everglades is oxidized this way [Westermann P. 1993. Wetland and swamp microbiology. pp 205-238]
Some people lay down peat in nylons, but then if you need to replace or rearrange plants, kiss their roots goodby.
Using this technique would be horrible, I'd strongly recommend leaving the peat simply scattered and mixed into the bottom 1/3 of the substrate.
Coloring the water is another thing. Again, speaking of peat, it will give the water brown-yellowish color that will never disappear.
Again, the small amount of peat being used does not have any noticeable color change. But even if it did, which it doesn't, using a bit of fresh
AC briefly in you filter will remove the yellowish tint.
Another thing to consider is that it will make water acidic.
Having had extensive experience with peat both for supplementation to new substrates and filtering with peat to try to soften water I can speak from long term personal experiences.
1) The amount of peat added to the new substrate should only be about a handful per 10 gallons of tank. This amount will not cause any tinting of the water nor will in have any impact on pH...except at the very initial first few weeks the tank is being established...this is mainly a result of the
CO2 being produced. The amount of humic and fulvic acids released from the peat won't play any significant or measurable role in the tanks ecology.
2) Peat softens water based on the pH of the peat and the dwell time to volume of water. There isn't any set point the peat will drop a pH too, other than when the peat is "spent" the effects will halt. When this occurs will depend entirely upon the pH of the peat, the amount of peat being used compared to the volume of water. Meaning peat with the pH of 4.5 added at a rate of 1 gallon of peat to 1 gallon of water would have a much greater softening and pH lower effect than would Peat with a pH of 6.0 and using 1 quart of peat to 5 gallons of water. Peat softens water by exchanging
Ca++ and
Mg++ ions for H+ ions thus reducing the hardness and lowering pH.
I think I read somewhere that it takes the pH down to 6.8 dead on.
Not the case, see the above explanation.
Considering above, you can barely find peat in
lfs, and that's not because they don't want to sell it, but because fewer and fewer customers are interested in it.
I can purchase a lifetime supply for about $3.00 at a local nursery. Why would a
LFS carry it. They don't carry Eco-Complete at any of my
LFS either, but it's still an excellent choice and product.
LFS don't carry KNO3, K2SO4 or Fleet Enemas, yet they are extremely valuable to the planted tank enthusiast. Heck, other than Hagen's
CO2 system you can't find
CO2 equipment locally at fish stores either...it they must be purchased online or from welding supply companies, my point is availability isn't an indicator of need or desirability for a planted tank.
Again, please don't misinterpret my intent of this post. I agree that adding a 1 or 2 inch layer of peat to a tank is a poor idea. Certainly experienced and well informed aquarist can use soil tanks successfully following the Diana Walstad method but a beginner should probably only add a small amount of organic material to a substrate. Using the recipe I posted earlier has been used and repeated successfully literally dozens and dozens of times.
