Re: Peat; good or not good

As a followup to Steve's comments....

>Well, what I think I meant to say was that Neil has been using peat in
>substrates and might quibble with a blanket statement that peat
>is not a good idea in substrates.

Yes this is true. I definitely think that peat IS a good choice. I do not
use heating cables and have relatively soft water, so these comments may not
apply to other situations.

Among all substrate materials - soil, clay and peat, I have found that peat
has been consistently good for me. It does well with an without added CO2.
Soil can be very variable. Once you have a good source of it, however, it
can also be good, and even better than peat. I have tried backyard clayey
soils and subsoils and also find them to be variable and potentially toxic.
WIth extra water changes and given enough time, they become stable. But,
this is a painful process to endure. 

Once a soil settles in, it seems to last a long time; at least until it
becomes packed with too many roots.  In all my tanks, I don't vacuum the
bottom. THis is something that would be very difficult with these added
materials. This is probably an advantage with a granual laterite. Regarding
disturbing a peat substrate, I tried to clean up the bottom of one of my 2
year old peat/sand substrate tanks recently. It had developed an unsightly
layer of mulm or peat which somehow got on the top layer. The extra layer
added an inch to the existing 3 inches.  I think from borrowing aquatic
worms. This tank had developed an algae bloom and now after 2 weeks has
still not recovered. The plants are crypts and chain swords and are not fast
growing enought to soak up the nutrients which apparently were released from
the "cleaning." As long as the nutrients were below the protective top
layers, they did not cause any problems.

> My impression is that with peat, there is still a good opportunity
>for a fair amount of further microbial activity which could release nitrates
>and various gases.

Due to the low pH of peat, I believe that this process is very slow. (the
low pH also makes more CO2 available). I think that small release of
nitrates can be beneficial (if it does release nitrates and/or phosphates),
if you keep few fish and feed little amounts, like I do. With more food... -
more plants or faster growing plants are needed to keep up with whatever
nutrients that peat release. For me, the peat is good in that I do NOT have
to add trace elements. I suspect, but do not really know, that decomposing
under a protective 1-2" layer of clean sand, it might slowly release iron
and other needed trace elements. 

>I think most people would agree with the statement that laterite substrates
>are fairly safe (and productive?).

They may be more safe, but must be supplemented with fertilizers or trace
elements. This is more work :-) but is probably better and safer approach
for the beginner. It also allows more control.
>Its a bit early, but there seems to be evidence that certain soil
>containing substrates also improve the algae situation. I guess it could
>be that any substrate which gives the plants an edge over algae would
>do that. 

I don't think it is too early. I would say the statement is true. Soils have
a longer lasting supply of iron than laterite; with soil, you do not need to
add iron. By keeping the iron in the substrate and having less or none in
the water, the algae doesn't do as well.

Neil Frank   Editor of "The Aquatic Gardener"  Aquatic Gardeners Association
 Visit the AGA home page at <http://blake.oit.unc.edu/~fish/aga/>