Ok, further to my post above, I have done some more research today and I may need to rethink the geo's...maybe a species only tank would be best...or maybe some rams & tetras will still work. The initial plan (determined partially by budget) is to house 6 medium discus in the 125 gal.
I am still thinking some basic plants attached to wood (anubias, java fern, etc) and leaving the substrate planted plants out of the picture. I do think I will begin with a thin layer of inert sand and have a basic river stone and root wood aquascape that enables effective cleaning.
My 125 gal currently has the rear glass painted black as that really enhanced the coloration of my cypho's. I think I have settled on either 4.5" valentine, 4-4.5" red melon/golden or 5.5" blue diamonds with teh dark blue gene, as the bright coloration really appeals to my wife & I, and they're stunning. Is the black background going to make the discus darker or will their colors pop nicely if the water quality and overall environment make them feel secure & happy?
Is 1 x 300W heater going to be enough to get my temp to 82-84F?
Thanks for any advice