Re: Vermiculite and Peat Moss and Aluminum

>From: Stephen.Pushak at hcsd_hac.com
>Date: Fri, 25 Aug 95 18:23:18 PDT
>Subject: Re: nutrient diffusion into vermiculite

>In nature things have reached a long term equilibrium; organic 
>materials decay; roots penetrate. We have to avoid creating
>unacceptable conditions such as putting too much undecayed organic
>material in the substrate. That is why peat and peat moss mixtures
>like potting soil are to be avoided entirely.

I STRONGLY disagree.  Peat definitely works. It is one of several materials
I use. Perhaps it needs enough plant and root systems to keep the bottom
-I have one 70 gallon tank for over 3 years with a coarse sand + peat
substrate.  No CO2, 80w fluorescent lighting; very successful. For first
year I had CO2 and 160 w lighting. Echinodorus tenellus var. parvulus, E.
quadricostatus,Cryptocoryne nevillii, Cryptocoryne pontederiifolia,
Cryptocoryne retrospiralis, Cryptocoryne wendtii, C. undulata, C....
Hygrophila polysperma, Mayaca fluviatilis, ... The entire bottom is covered
with the chain swords and Crypts.  Obviously, no gravel washing!  I have to
thin the Chain swords just to see the crypts and give them a chance to
spread. Very little algae.  Major algae problem is an occassional outbreak
of a green thread like algae that gets tangled with the bottom plants.
Solution is to cut down on feeding to reduce water borne nutrients. The tank
cycles thru different bottom plants.  At one time it had mostly E. tenellus
var. tenellus and quadricostatus.  Now, var. parvulus dominates.
- I have another tank (40g: 36"x16"x16") with coarse sand,  peat and
vermiculite; set up around Jan 95.  Also without CO2. and doing well. I
think that the softer substrate will be better in the long term.  Growth is
not as dense (yet), some different crypts, all doing well except for C.
affinis. This is a very finicky plant, so difficult to draw conclusions.  I
wonder though if the vermiculite is providing something (like Aluminum) that
the affinis doesn't like. Is it possible to have aluminum toxicity. I know
that my supply water has Aluminum added.
--btw, I think these tanks do well without CO2 because of the slow
decomposition of the peat, the acidic environment caused by the peat and
the conversion of bicarbonates to CO2 under these conditions.
- My second vermiculite tank is another 40g side by side with the above,
with identical lighting, but with a sand/verm/soil substrate. Also set up
jan 95. From the beginning it didn't do as well and has had problems. I
added yeast CO2 after major algae problem (too much nutrients).  Accelerated
plant growth controlled the algae, but plants have never looked right and
others would not grow. I am now going to tear the tank down and try another
system. Too many choices!
 -- I think that the soil had too much of something and created a toxic
environment. The soil was purchased - top soil that looked and tested OK.
This is not to suggest that soil is always a bad idea.  I have had better
success with soil from my back yard; it is just a pain to separate the tree
roots and rocks. Peat is much more predictable.