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Re: Aquatic Plants Digest V3 #1237

>From: "Knight, Richard" <rjknight at meto_gov.uk>
>Subject: Changing swords
 My problem is with my chainsword plants,
>E.tenellus and another I bought under the name of pygmy chain sword. The
>tenellus when planted started life with 3 inch stems with narrow tapered
>leaves at the end about an inch long. The pygmy chain started with a small
>crown of leaves about 1 inch long and half inch wide tapering to a point.
>The problem is they both now look like vallis as all the new growth is
>slender quarter inch leaves from start to finish and the only way to tell
>them apart is height!
>How can I get them to grow in there original shape??

The shape of the Echinodorus tenellus and related species may change due to
changes  in environmental conditions, most notably the amount of light and
the amount of crowding. Changes in nutrients may also be a factor. In your
case however, I suspect that the change is due to the acclimation from
emersed to submersed conditions. Most plants sold today are grown by
nurseries hydroponically... with their leaves out of the water. If you want
the leaves to return to their previous condition, drain the tank and keep
the roots wet and surrounding air moist.<g>

I have 2 of my tenellus pictured on a temporary web site I did last year
when I sold some plants. You might see a chain sword that looks like yours.
One of the species (or variants) is shown grown under different conditions
and you will see that the plants look quite different.


>From: "Roger S. Miller" <rgrmill at rt66_com>
>Subject: Re: Sera fertilizer

>Incidentally, dissolved iron in unpolluted natural water is generally in
>the parts per billion range - 50 parts per billion or so is fairly
>common.  The EPA limit for domestic use is 0.3 mg/l of iron, and their
>limit for protection of aquatic life is 1.0 mg/l.  Why would we ever need
>0.5 mg/l of iron in aquarium water?

Simple... in nature, there is an unlimited supply. Generally, there is
plenty of iron in the substrate... and even if there weren't, there is a
constant supply at the naturally low concentrations. In a closed system
without a refreshable supply, it must be added periodically. Otherwise it
goes to zero. I suspect that you could do well with actively growing plants
if you maintained a small but measureable amount (say .05ppm) as long as
you keep it replenished -- perhaps by adding a new small amount many times
per day (i.e. after measurements showed that the Fe was zero). I personally
prefer the approach of adding the appropriate amount once per week. Towards
the end of the week, the Fe concentration drops off... but that suits me
fine. Otherwise I end up with too many or gigantic plants.<g>