Subject: Re: NANFA-L-- Native Aquatic Plants (LONG)
From: Laura Burbage (leuhrich-in-yahoo.com)
Date: Thu Jul 29 2004 - 13:05:25 CDT
Todd,
I had so many thoughts, I had to print out your
message and think about it! :)
OK, heres my take - I must preface this with the fact
that I keep low-tech tanks. I am in no way claiming
that the high-tech stuff is junk, just that I don't
use it and don't seem to need it. Some people like
the high-tech stuff, and some like to see just how
fast they can get their plants to grow. I just like a
nice, easy, planted tank. So please, no flaming,
anyone. :)
Cyanobacteria (aka blue-green algae)- sure I get it.
It is supposedly also very common in new tanks. I
don't think the bare soil has anything to do with it -
I actually never got it in my bare soil stuff. It has
more to do with nutrient loading issues. The common
thought has always been that it is from a low N:P
ratio in the water, because many cyanobacteria can fix
nitrogen. The thought is that these algae can then
outcompete other algae and plants and can absorb the P
without needing additional N. Very recent studies are
suggesting that it is really more of a general
nutrient loading problem, especially with high P
levels, and that low N levels may not be to blame, and
that N fixing by cyanobacteria is not increased under
these conditions. E.g., if you have very high P and
moderate N, raising N will not necessarily fix the
problem. I get cyanobacteria in my tanks that have
high light and are fed very well (I tend to be an
Armenian grandmother with my fish - eat! eat!). I
have never had cyanobacteria in tanks that no not have
fish in them.
It is difficult to keep P under control sometimes.
For some people, simple water changes can help. For
me, they can make it worse. My city water has a lot
of P in it. Many municipalities add P as a
corrosion-control agent to keep lead and other metals
from leaching out of pipes. Controversial, yes,
because it increases P loading in aquifers and after
the wastewater treatment plant.
P is removed from the water by colloidal sediments
like clay and fine detritus. So, interaction with
bare soil can remove P. In the bottom layers of the
sediment, where soils are anoxic, P is released and is
available to plant roots. Mixing this soil will
release the P to the water. Some ponds get spring and
fall algae blooms when their water mixes-in-that time.
Many aquarists think anoxic sediments are bad. I
don't. Sediments in natural ponds are anoxic below
about the first 1 cm. Aquatic and wetland plants have
special adaptations to deal with anoxic soils. The
only problems I could see is that if you mix them up
_to_ much, you could release toxic substances to the
fish that are normally bound up in oxygenated water.
A little soil mixing is fine (planting or moving a few
plants), as any release is small and gets oxygenated
quickly. Oh - and I think there may be some tropical
plants that need lighter, more oxygenated sediments,
but I don't know anything about those :)
You can also buy things to remove phosphorus.
Phos-zorb, phosguard, etc. There are also additives
you can use like ferric chloride or aluminum sulfate
(alum). Or you can use DI or RO water, as long as you
reconstitute the necessary ions back in. Some pH
buffers have phosphorus, so look out for those.
Of course, you should plant the tank densely, which
will help keep phosphorus bound up into plant tissue.
Some plants like water sprite and Ceratophyllum also
float and are good nutrient removers.
You can also kill cyanobacteria using 1/2 dose of
erythromycin for about 3 days. But, it _will_ come
back. You can also kill it using hydrogen peroxide
squirted directly on to it (this works for any algae).
The whole tank can be treated with 1 oz of hydrogen
peroxide (3%, the pharmacy kind) per 10 gallons. So,
to spot treat in a 55 gallon tank, you could put 5.5
oz in a syringe and squirt it directly into the algae
in question. Generall occasional dosage keeps algae
down.
OK, let's see... my take on fertilizers and
fluorite... Most aquatic and wetland plants absorb
nutrients best from their roots, not the water column.
I think the liquid fertilizers are a waste of
cashola, and can contribute to algae problems. Use of
soil or clay will help keep nutrients-in-the plant
roots. While sand looks nice, it also keeps mulm
(containing nutrients) from the plant roots. Some
plants are pretty heavy feeders; I think Vals are one
of those. If I need to spot fertilize, I break up
some little miracle grow sticks into tiny pieces and
push them into the soil-in-the plant base. People buy
flourite because it has a high CEC(cation exchange
capacity) which binds nutrients, but clay and organic
material have higher CECs, and allow the plant roots
much more surface area to pull the nutrients off the
particles. However, I do agree that fluorite is
likely better than plain sand or gravel, especially in
a new tank where there isn't any accumulated mulm. If
sand is needed for a particular fish, then I might
suggest either putting sand over soil only in certain
areas of the tank, with gravel in others to let the
mulm fall through, or just not making that tank a
planted tank. OR, I've been thinking about
experimenting with this in my brackish tank (which has
sand for the hogchoker)putting some plants in clay
soils in tiny plastic (homemade) pots with holes
drilled in, then putting these in the sand. We'll
see. Could be a complete disaster, especially with
higher light and not enough plants.
Regarding your problems with Bacopa, etc. My Bacopa
grows like gangbusters in the soil. It is wild-caught
:) but I would think that the stuff in stores would be
more likely to grow in gravels, since it is
artificially selected (by consequence, not design) for
these types of systems. Good lighting is also
required by many plants, Bacopa included. You don't
need to buy expensive plant lights - cool white
fluorescents work just fine, a mix of cool whites and
warm whites can work a little better and look better,
too in my opinion. The issue is really of intensity.
Expensive aquarium compact fluorescents can achieve
this, but I think they are only necessary if you
really need to keep temps down or can't fit enough
regular tubes over the tank. They also save some
electricity over regular tubes, too.
If you haven't figured it out yet, my take on most
aquarium (ESPECIALLY plant) products is that these
things are sold because they have great marketing.
And marketing is nothing but a way to try to separate
me from my money. They will convince you that all
this fancy stuff is needed to grow plants, and it
really isn't. I use no CO2 systems, no expensive
lighting stuff, no special gravels, no liquid
fertilizers. I buy just about everything-in-Home
Deopt, Lowes, or electrical stores. Just about
everything except the tank itself, air and water
pumps, and some chemicals like dechlorinators or
medications. (I make my own sump filters, light
hoods, etc. It's not hard, and the stuff that is
pre-made is not made of anything fancy!)
AND I spend a WHOLE lot less.
-Laura
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: Wed Sep 29 2004 - 12:21:36 CDT