fw:Re: What's this plant? & Substrate heaters

Here's some email from Steve Pushak he asked me to forward.


---forwarded message---->

Wed Apr 19 15:12:00 1995

 To:         Shaji (S.)  Bhaskar                (BNR)      Dept 3X12   BNRTP

 From:       'Stephen.Pushak at hcsd_hac.com'                     (BNR400)

 Subject:    Re: What's this plant? & Substrate heaters

 Attachment:  1) UNIX File: ORIGINAL.HEADER - 640 bytes  

 Sent by:    'Stephen.Pushak at saudan_hac.com'                   (BNR400)

Re: Substrate heaters

When you first described your design for the UG heater, I envisioned wrapping
the wire wrap in a tight spiral around the clotheline wire so that the whole
thing resembled a long flexible heating cable, as opposed to something that
looks more like a loom with lots of thin wires woven back and forth. I must
caution you (and all) that amperages more than a few milli-amps can be
quite *fatal*! The power supplies and transformers which you are planning
to use are capable of delivering *lethal* currents. Normally when you wire
your house, a building inspector comes to check things over and there are
strict codes to follow. What we are suggesting violates all sorts of things
you would never do in your home. For safety sake, you *MUST* ensure that
there is adequate insulation. Especially if you have children (or anyone
else) even the terminal connections should be enclosed. (Imagine tiny
wet fingers *shudder*!) Wire wrap usually comes on a spool of some sort so
winding may be tedious but not impossible. How about this design:
wrap the wire wrap around your 30 foot vinyl-steel clothesline core. Solder
the joins and seal with a short piece of shrink tube. Solder some heavier
gauge wire to the ends for making connections. Now wrap the whole length
with electrical tape; that offers a degree of protection for the thin
insulation on the wire wrap wire. You could even double wrap it. This will
provide mechanical protection for the insulation but won't prevent water
from going inside the electrical tape. You could put the whole thing inside
a thin flexible PVC tube to provide the water barrier. The PVC tubing is
long enough to extend right up out of your tank and is *secured* to the 
outside of the tank so it can't slip in. You'll have to be inventive to
thread it through the tubing but try getting a weighted cord through first ;)
The PVC tubing must be flexible to provide a good thermal contact between
the heater bundle and the tubing wall. I don't have the thermal conductivity
co-efficient for PVC handy but perhaps an enterprising engineering type can
track this down. After all, the external temperature of the PVC will never
exceed about 100F and probably 85F is more accurate. My gut feeling is that
it won't get that hot inside (150-200F) which is fine for PVC and electrical

Re:What's this plant?

Shaji, my book describes Ammania senegalensis and says there are 3
varieties: two green and one red. The red variety has ovate leaves 25mm long
and 10-12mm wide, with undulate margins. The flowers are pink or reddish
and 5-7.5mm wide. It also says the stem (describing Aman s. generically)
is 2.5 - 5mm thick and reddish. Sounds like some of the unidentified plants
in my tank (reddish-green to green leaves ovate but the largest leaves on
mine are only about 10mm long). I also have descriptions and pictures of
Didiplis diandrai, Rotala macrantha, R. rotundifolia and R. wallichii.
Sorry, no mention of Ammania gracilis. My book is "Aquarium Plants" by
Dr. Karel Rataj and Thomas J. Horeman. (c) 1977.

But my other book "Aquarium Plants Manual" describes only Ammania gracilis.
"Stem plant about 50 cm tall. Leaves sessile, decusssate, narrow-lanceolate,
olive-green to reddish brown." The picture shows rather longish leaves rather
than the oval ones above. The plants I have look more like the Bacopa 
caroliniana in this book which have the ovate shape. Did your plant have
ovate or longish leaves?