But I am concerned about
the biological filtration of the wet/dry robbing nutrients from the plants.

Don't be. You will have plenty of nutrients and adding KNO3 is simple
if you need more NO3, topping off with KNO3 is ideal and what folks
want.
Any build up of NH4 and that spells trouble and algae.
The bacteria will not remove any PO4, K etc, plants will. It's mainly
the N compounds that are removed by bacteria in larger amounts.
Bacteria are a back up for the plants should excess NH4 be produced
froma heavy fish load or a high feeding rate or large disturbances to
the tank's plants(This can be in the form of a large pruning, poor NO3
levels which result in stunting of the plant, PO4 levels at or near
zero chronically, no CO2 etc).

Better to have bacteria than algae.

It is much better having NO3 in a tank which wet/drys are very
effective at converting the NH4(Food, fish waste) into NO3 which is a
good thing for plants as long as it's not too high (15ppm or less).
Plant are rather effective when healthy at accomplishing this removal
and seem to get to the NH4 before the bacteria do.

Wet/dry sump maintain a constant water level in the tank itself and
this allows for much easier maintenance and looks. They allow a place
to put everything like a good CO2 reactor, heater's etc. They are very
easy to clean the prefilter fast. I've never had to clean the bio
section ever. They remove only the water with the lowest dissolved CO2
levels in it and the highest O2 levels. No reflected light from a scum
surface layer so all of the light possible gets into the tank and the
surface is crystal clear.
1000GPH is fine at whatever head pressure the tank height requires for
that rate of flow. So for example, if the head pressure is about 4-5
ft, then you'd need a 1500GPH and at 4 ft it'd have about 1000GPH etc.

measures 7 feet long, and 2 feet front-to-back. Here's the kicker: it's 32
inches deep! Obviously this will take some serious lighting to reach the
bottom of the tank with any measure of intensity. How should I light it?
I'm open to all thoughts; Compact fluorescents, MHs, VHO, standard
fluorescents, etc. Keeping in mind these factors: long term cost of use,
replacement bulb cost and frequency, heat, and plant health.

What about getting in and out of this large garden which you will need
to get in and trim every often? I think access and ease of maintenace
is a huge issue.
Open top tanks with MH's are ideal for this tank type.

Don't make it hard to get to. Make a quick drain and quick fill device
on your main water pipe. Set this up so you can do a rapid water
change and refill without using anything except two ball valve to
remove water and one to let the water back in. If set up right, it
should take about 5-10minutes to do a 50% water change and not need to
lift a bucket etc.
Add fresh plant nutrients back, and repeat weekly.

Up front cost is not really an issue in this case.

They make rather pricey electronic MH ballast but they are 100%
silent, use less electric, burn the bulbs brighter etc.
Getting the most out of your electric and making into light for the
plants is the big goal and also using bulbs that don't cost an arm.
The cheap bulbs in the 4300K range work super for plant tanks,
although some don't like the slight yellowish color. With open tops,
the yellowish color is far less harsh to folk's eyes. Run about
12-19$. 5500K 6500K run about 40-80$.

I'd go with 3-4 x 175W. You can buy the Advance tar ballast and DIY
much cheaper.
They sell the pendant globes with light socket wire etc for about
40-60$ each. Just add ballast(for the electronic version) and coil for
the tar.
Run the wires through the wall etc to make it look nice.
You can have a light rail type box made at a sheet metal shop made
from aluminum at a reasonable rate and suspend it.

You can plant house plants around the tank, on ledges etc near the
tank so to take advantage of your spill light from the MH's. This will
also blur the aquatic realm/ part into the terrestrial portion of the
house. It makes the area feel like a jungle/garden, so rather than
looking into a frame, you are actually part of the scene since it
comes out past the tank into the house.

Regards,
Tom Barr




Scott