Oceanic canopy... does this mean the (polo?) light assembly and the
two glass tops (4 panes and 2 hinges)? iirc, the Oceanic top trim has
a centre section, but I don't think I've seen a 55g Oceanic.
Glass can be obtained at any hardware store, though Oceanic uses a
slightly thicker glass than normal. This is important if you are
using the Oceanic plastic hinges. Hagen hinges would probably be too
tight, so you need to match glass to hinge (iirc, there are 3
commercial thickness grades used). If you do have the centre trim,
another option is the sliding glass (no hinge). The front pieces
slide under the back (uses a 2 track trim on the sides to keep the
panes at different heights). These can be very convenient, but watch
that the light canopy does not interfere with the sliding operation.
For lighting, there are lighting units which have a side piece which
wraps around the tank, and others float along the top. Then there are
the aftermarket lighting upgrades which typically float so they don't
need to worry about the exact tank length. As long as you can get the
48" T6s or T8s in there, it doesn't matter too much.
Oceanic sells their standard and upgraded light canopies alone. I
once installed an upgraded Oceanic canopy and the heat cracked the
glass top, which is how I remember their glass being very thick. Your
local fish club is another resource. Also if the tank is old, you
might be able to find a dusty canopy in some pet shop. We would
sometimes order canopies and customers didn't pick them up (or we
would order an upgrade and shelf the standard light which came with
the tank kit). Every store has an oddball collection. Be sure to
negotiate based on how thick the dust is ;~) but unless you keep a
poker face, they'll probably know they'll be able to get full price
from you (which unfortunately is a small ransom when it comes to
Oceanic).
As for the tank under the TV look, I'd mount the TV about 12" off the
wall to keep the front surface closed to the front of the tank, but
still behind the front hinged glass top. I'd also consider chopping
the tank stand down. A couch sightline is going to be around 38-40"
so you don't want to arch your neck upwards to watch TV. It also
provides more gap between the light canopy and the TV (for heat).
Ideally, the light canopy should be opened at the back, so it is well
ventilated and the heat travels up the back of the TV (not into the
bottom of the TV). The escaping light reflects off the wall giving a
backlight which is sometimes desirable for TV viewing. You might want
to experiemnt with this yourself to see what your preferences are.
Look for a TV wall mount which will let you pivot the screen out of
the way for tank maintenance. This can be very important for corner
installations and HOB filters. Canister filters are the best choice
for under-TV installs (because of the lower noise, better maintenance
access and no water loss (humidity created) as TVs don't like a
humidity source underneath them (especially marine tanks ;~)
have fun!
NetMax