New Plant Tank Advice?

Hi!  I've been lurking on the list and reading the archives for awhile now,
and while I've been keeping fish for the last 30 years or so, I'm just
getting ready to set up a reasonably serious plant tank, and would like to
get some advice as to where I'm going, and maybe get one or two questions
answered where I'm still confused...  

The tank is a custom tank, roughly a cube 30" square.  The goal is to get a
reasonably lush planting that takes advantage of the height of the tank, and
lightly stock the tank with discus and cardinal tetras.  Additionally, I've
got some tropical bog plants (black princess taro and dwarf umbrella palm)
from my koi pond that need to be brought in to be wintered over, and I'd
like to find some way to arrange these in the (open topped) canopy so that
they're taking advantage of the light and nutrients, and show to good

Here's where I am so far...

Light - I've got a 250 watt "5500K + Daylight" MH pendant coming from
Hamilton. The challenge here will be to arrange this high enough that it
lights but doesn't cook the bog plantings, while still lighting the
submerged plants and not going over the edge of the tank and flooding the
room.  I also plan to supplement this with 1 or 2 NO fluorescents, so that
the MH can be on 10 - 11 hrs per day, but there can still be some light to
enjoy the tank for a few additional hours.  I was thinking of cycling the
lights with a timer so that the fluorescents come on two hours and then off
when the MH comes on for 11, and then the MH off and the fluorescents back
on for another 2 hrs.  Will this additional light disrupt the plants
tropical light cycle too much, or will it be unnoticable compared to the MH?

CO2 - I've also got Hamilton's CO2 injection kit coming, which should be
most everything but the bottle (20 lbs sounded like it was lasting a year or
so for most folk - is that about right?), and I'll be using this with a
Sandpoint Accurate-1 pH controller.  I want to target a pH of around 6.8 for
the discus, although this could move up or down a little depending on what
the plants need most.  Has anyone used the Hamilton's kit with the Sandpoint
controller?  Any "gotchas" that I need to worry about?

Substrate/Heat - At this point, I've pretty much decided to try to avoid
doing substrate heating (commercial systems too expensive, DIY wire too
risky with my competence :-), and DIY pvc/heater systems too messy
visually), and go with a vermiculite/loam/texblast mixture - it seems like
(reading some of the debates in the archives) laterite pretty much requires
substrate heating to keep it from going anerobic, and "cold floor" tanks
would probably do better with something that doesn't compact as much.  Is
this a fair assessment?  If so, can anyone in the Dallas / N. Texas area
recommend what "loam" might be packaged as in the garden shops?  I don't
recall seeing anything saying "loam" in particular...

That having been said, I wandered into a local shop this afternoon, and
found on the $1.00 closeout shelf some "Duplaflex S" substrate heating
cables (at least I =think= that's what they are - my German's less than
useless).  These read "100 Watt, Spezial Sicherheitskabelheizer 42 volt".  I
got three of them (all they had), and each has around 2 meters of 2
conducter flexible (silicon?) cable, with some sort of inline bulge at each
end, followed by a banana plug.  There are also a couple of suction cup
holders, and I found three packs more of the holders as well on the same
shelf.  No instructions. Could these be used to leverage a reasonably cheap
substrate heating system?  If so, what else is needed?  I can run a
soldering iron middling well, but I'm far from an EE.  In any event, I plan
to run a pair of Ebo Jaeger 150 watt heaters to keep the tank up to discus
temps (82oF - 84oF), so it wouldn't need to do more than provide substrate

Fertilization - No idea.  Something reasonably low-tech and low maintenance,
hopefully.  My tap water comes out at a pH of around 8, with vanishingly low
alkalinity (your average biofilter will drop it like a stone without buffer
support).  GH unknown (I've not needed a test kit for this for years, so I
haven't checked it yet).  I'm a reasonably large consumer of lily pond
tablets, and have a fair amount of these around if they can be put to use...

Plants - likewise no idea.  I've got a bunch of Anubias nana around from
another tank that I'd planned on using, and would like to have some
Hygrophilia and a radicans sword or two, but no preconceptions beyond that.
I'm particularly unsure of ideas for tall plantings to take advantage of the
height of the tank, other than something like "jungle val.".  Any
suggestions on what might work well here?  I'm not looking for something
challenging as much as "what will thrive" in this kind of environment.

At any rate, any advice, warnings, etc, would be very welcome.


- Chuck Lawson

clawson at onramp_net