Bottom 55 gal tank with fish?

Hi Folks:

I have a 55 gal planted show tank with some discus, cordy cats and
various neon and a pair of German Blue Rams. The bottom of the stand looks
inviting for another 55 gal and since I have an extra hood and heater I'd
though I'd put another 55 gal one below the top one.

My main concern is the low placement of the tank. It would be of
course at knee high, and while that's fine for sitting and watching the fish
I worry about 'spooking' them when I get up to arrange thing in the top
tank. I'm not particularly 'set' on any one type of fish in the bottom
tank, but I think discus would be a problem as I understand they 'spook'
easy and like to see you at eye level.

Any suggestions for some fish? My water is blessed at 6.2 pH and 3 KH
straight from the tap. I'm kind of new to the hobby but love South African
Dwarf cichlids and cardinals and such. Of course I can treat the bottom
tank as a quarantine tank but I'd like to make it a thing of beauty too!

My other concern would be weight. 2 full 55 gallon tanks are quite a
load! Any suggestions/comments or advisement appreciated. Thanks for
holding my hand!

Jim C.
P.S.
I bought my above discus two weeks ago and am now IN LOVE with the
species. I have them eating out of my hand! I have two and just bought 4
more through an online breeder. What great fish!