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Re: Aquatic Plants Digest V2 #614
Subject: R.macrandra, H. polyperma and tank conditions
>One set of plant responses take place at so-called typical water chemistry,
>but other things seem to happen at lower and higher levels of various
>chemicals. Copper and other metals are another wild card, and Karen's hard
>water laboratory may be different than other hard water environments.
I'm sure that my water is different from some "hard water" sources. First,
of course, there are places in the country that the tap water is _much_
harder (both KH and GH) than what I have to deal with. But also even among
those of us with only "moderately hard" water there are differences. There
are a number of "hard water plants" that do very poorly in my particular
hard water. Some of those are specifically known to be copper sensitive
like Val and Sag, but there are others that I do not _know_ to be copper
sensitive, like Hornwort and Elodea that turn to mush almost immediately in
my tanks.
>I have subjected H. polysperma to 0.5ppm Cu in my soft water and at that
>concentration polysperma is not sensitive. THis is the concentration that
>kills many algae (incl. red algae (Audinella)) and some plants like
>Vallisneria. Now, polysperma and all living things are going to be sensitive
>to ionic copper at some concentration. If Karen's copper levels are higher
>than 0.5 (I think she mentioned 3ppm!), this is likely to be fatal.
The 3ppm is out of the tap, not the concentrations in the tanks. I try to
keep the concentrations in the tanks no higher than .25ppm
>It may
>be the reason that she needs soil for polysperma. The organic material of
>the soil will bind with copper... and make it much less toxic.
>So in addition to excesses which create problems, we must also consider the
>counter acting influences of other things (like organics or chelators).
A lot of copper precipitates out just because of the hardness of my water.
At the times when copper is the highest, I can find a blue precipitate on
the bottom of a bucket of tap water after 24 hours. (it is blue, honest,
even in my green buckets ;-) I'm not sure how much the soil would help for
this specific purpose, because the amounts of soil I use are rather small,
and usually in pots, not at large in the substrate.
>Are we having fun!
Yes. THIS is what I love about this list.
------------------------------
Subject: Algae Farming
>On Algae Farming,
> Yes, we are all algae farmers to some degree. However, the amounts
>and the kinds of algae tell us a great deal about whether we are doing
>things "right" in our tanks. Let's talk about balance again. The type,
>number of plants, amount and duration of light, available CO2, and the
>amount of fertilizer added, are just some of the factors that we need to
>keep balanced.
> Now about your problem, I think that most folks would agree that you
>have "bad" algae, and maybe more than one kind of it at that. Here are
>some things that might help:
>1. Don't panic. Some algae, and sometimes even a lot of algae, is normal
>in a new tank.
I agree with most of your post on algae and algae control techniques. But
I have to say that I _don't_ consider it "normal" to have much of any algae
in a newly set up tank. I think that everyone here knows that I use
_mostly_ laterite in my substrates, with soil usually only in pots for the
plants that really need it. I would have attributed my lack of algae to
the fact that there are less organics in my substrate. But about 6 months
ago now I set up a tank (the infamous Robbie's class room tank) with a soil
substrate. That tank has had _no_ algae problems from day one either.
---------------------------------------------------
Subject: Potting Soil Trouble
As another example of how things can unexpectedly go wrong with organic
substrates, I'd like to tell you about a recent discovery in one of my
tanks. As most of you know, I pot _some_ plants up with potting soil in my
tanks. I recently had a 55G tank that has been set up for about 3 years
where things just weren't going as well as I liked lately. I had been
toying with the idea of setting up a large soil substrate tank for some
time, and I thought this might be a good time to try it. I had a soil
source that I had used successfully in a small tank, and had decided was
safe for the substrate in the large tank.
To digress, when I visited Neil at the beginning of March, I came home with
a number of plants,. Since some of them were new to me. I decided not to
take any chances, and to pot them up with potting soil. These plants were
all in the tank I was going to take down.
Normally, when I pull one of my potted plants, either to move it, divide it
or re-pot it, there is absolutely _no_ odor. When I removed these plants,
they stunk!!! the smell was overwhelming. I had used a potting soil picked
up at the grocery store, just as I usually do, although possibly a
different brand. I have kept the bag, (I'll use it only for house plants
now!<g> so that I'll remember what brand _not_ to buy again!
Fortunately, it seems that just by chance I caught it before things went
too far, and the plants are, for the most part OK. There was one large
Sword (E. 'Oriental') that had some brown areas on the roots, but I cut
these out, and I think there were enough good roots left that the plant
will be fine.
SO I guess the moral of the story is, if you are playing around with
organic substrates, even if you've done it a thousand times before, make
sure you are confident that the MATERIAL is the same as what you've used
before.
Karen Randall
Aquatic Gardeners Association