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Re: Aquatic Plants Digest V3 #336

Subject: slow UGF

Steve wrote:

>I don't know what an optimal flow rate would be through the substrate. I
>think I based it on an estimate provided third hand by Karen R which was
>something like 24 hours or more for water to move from the substrate
>surface down to the bottom. 

I don't think this came from me.  I've never had much interest in
quantifying the subject beyond saying that you want it to be "very slow".<g>

My personal opinion on this subject is that I'm perfectly happy with the
job the plants themselves do moving water through the substrate.  The only
time I would strongly consider substrate heating are in those cases where
room temperature tends to keep the substrate substantially cooler than the
water column.  I don't think this is the best situation for plant roots.
In these instances, my prefered method of integrating the substrate is to
use a UG plate with 7.5W heaters in the uplifts.  This provides enough
current to bring the substrate temperature back in line with that of the
water column.  Since that is my main goal with these systems, the _very_
small amount of movement is "enough".


Subject: Questions about water circulation

Reid Kerr wrote:

>Disclaimer:  I have absolutely NO experience with these matters, just a

>Rather than using a powerhead to generate flow, would it be possible to
>use a wide, shorter lift tube, with a submersible heater positioned
>directly IN the lift tube?  In this way, one might be able to use
>convection to generate EXTREMELY gentle water flow, much more so than
>with any pump.  Has anyone contemplated/tried this?

Actually, I wrote the above response to Steve before I saw this post.  Yes,
I was first introduced to this method by Claus Christensen a number of
years ago.  I have written about the method several times in various
publications including AFM and TAG.  I have used the method successfully a
number of times, as have a number of other people.  There is no question
that it works.  The question is how much benefit it (or any substrate
heating system) is.  As I mentioned above, I would use them in any
installation where the substrate was likely to remain substantially cooler
than the water column without circulation.  IMO, in most situations the
plants move adequate amounts of water through the substrate themselves.


Subject: Aluminum Plant

>At my LFS last night I noticed some aluminum plants for sale, remembering the
>discussion here I became mildly curious.  Doesn't a LFS have some sort of
>liability for selling a product that has no biological chance of surviving in
>the medium?  

First, although I wish merchants were better informed, a lot of them don't
_know_ what plants are aquatic and what are not.  They order "mixed plants"
from the wholesaler, who may, himself, not  know anything about plants.

Even those merchants who _do_ know that these plants are not aquatic (and
aluminum plants are only one of many non-aquatics offered for sale as
"decorations") figure that the plants would die in most aquarists tanks
whether they were aquatics or not... I bet Rotala macrandra dies much
faster in most tanks than aluminum plant does.<g>

>There must be some legal remedy to discourage this practice.  All
>states have bad faith commerce clauses.  

First, you have to prove bad faith.  In most cases it's ignorance.  Second,
I beleive that in most cases, you can only recover damages.  What have you
lost?  $1.98 worth of plants?

> Perhaps this plant can survive and "our" experts are just not familiar
with it, or more likely the >plant has been misidentified.

Nope.  It's  (Pilea cadieri) and I've seen it offered for sale numerous
times along with other non-aquatics like Hemigraphis (Purple Crinkle,
Purple Waffle), Aglonaema, Syngonium, Ophiopogon (Mondo Grass), Lycopodium
(Princess Pine) Dracaena sanderiana (Sandy) ... Should I continue?

I believe our best recourse is education.  Teach people to be sure that the
plants they purchase are aquatic or amphibious.  Teach people to take care
of their plants well enough that they have a chance of surviving _if_
they're aquatics.  Point out non-aquatics to pet shop owners. (in a nice
way)  Offer to help them choose plants that will actually do well for their
customers from their wholesaler's lists.  

Growers keep producing these plants because, unfortunately, there is great
demand for them.  People like them because they die slowly :-(
Karen Randall
Aquatic Gardeners Association