Re: substrate heating coils

    From: "shaji (s.) bhaskar" <bhaskar at bnr_ca>
    > I finally broke down and decided to try DIY substrate heating. ...
    > I'm going to do this using 4 reels of 50-foot wire, wound in
    > parallel on a frame built of solid steel-core, vinyl-insulated
    > clothesline from my local hardware store. ...
    > The frame will be glued to a 46" x 16" piece of plastic carpet
    > backing and placed at the bottom of my tank. ...


    Is this "carpet backing" the white plastic mesh sold in craft stores?
    If so, you might want to rethink its use.  I experimented with the
    Radio Shack wire-wrap wire woven through sheets of this mesh in a
    serpentine pattern.  While the mesh protected the rather thin wire
    during the open-water experiments, the concensus of my friends and
    me was that the mesh would quickly get thickly matted with roots, so
    that pulling up plants would quite possibly damage both the plants
    and the heating coils.  I haven't gone any farther with experiments
    yet, but I've been thinking of a rectangular frame of 1/2" PVC pipe,
    with some number of small cross pieces (rigid air-line tubing?).  The
    wire would be spiralled around the cross pieces much as with your

    As an alternative, where might we find some high-resistance, thickly-
    insulated cable like that used by Dupla and Dennerle, but without the
    price associated with the (100% pure unobtainium, hand-crafted by
    Bavarian elves) german products?

    -- Keith

    | Keith Brummett            Ofc: 614-860-3187         AT&T, Room 3B202 |
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